Battery cell and power battery

Abstract

The utility model relates to the technical field of batteries, in particular to a battery cell and a power battery. The battery cell comprises a naked battery cell and a rubber coating part coating the outer surface of the naked battery cell, the naked battery cell comprises a positive plate, a negative plate and a diaphragm separating the positive plate from the negative plate, the width of the diaphragm is larger than that of the negative plate, and the part, exceeding the negative plate, of the diaphragm is connected with the rubber coating part. According to the utility model, by utilizing the rubber coating piece coated on the surface of the naked battery cell, the part, exceeding the negative plate, of the diaphragm is connected with the rubber coating piece, so that the outermost pole plate of the naked battery cell and the diaphragm are fixed into a whole, the diaphragm between the positive plate and the negative plate is not easy to slide, and the whole battery is not easy to slip in the whole battery test process. Even if the naked battery cell collides with the shell, the diaphragm on the outermost layer of the naked battery cell does not slide, so that the condition of micro short circuit of the battery is avoided, and the reliability of the battery cell and the power battery is further improved.

Description

Technical Field

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

[0002] Aluminum shell lithium-ion battery is a large-capacity, high-power battery mainly used in small devices. In order to consider the impact resistance of aluminum shell lithium-ion batteries in response to external forces during transportation and carrying, aluminum shell lithium-ion batteries need to be subjected to a whole-machine drop test before leaving the factory. In the whole-machine drop test of existing aluminum shell lithium-ion batteries, due to the gap between the bare battery cell inside the battery and the battery shell, the bare battery cell will slide back and forth in the shell and collide with the top or bottom of the shell. At the same time, because there is usually a gap between the positive electrode plate or negative electrode plate of the bare battery cell and the diaphragm of the bare battery cell, during the collision between the bare battery cell and the shell, the diaphragm is easy to slide due to vibration or extrusion, which will cause the positive electrode plate and the negative electrode plate to directly contact, causing a micro short circuit in the battery, and then causing the aluminum shell lithium-ion battery to fail. Utility Model Content

[0003] The technical problem to be solved by the embodiments of the utility model is to provide a battery cell and a power battery to solve the problem in the prior art that when the battery is subjected to a drop test, the bare battery cell collides with the shell, causing the diaphragm to slide easily after being vibrated or squeezed, resulting in direct contact between the positive electrode plate and the negative electrode plate, thereby causing a micro-short circuit in the battery.

[0004] The utility model discloses a battery core, comprising a bare battery core and a rubber coating member covering the outer surface of the bare battery core, wherein the bare battery core comprises a positive electrode sheet, a negative electrode sheet, and a diaphragm separating the positive electrode sheet from the negative electrode sheet, wherein the width of the diaphragm is greater than the width of the negative electrode sheet, and the portion of the diaphragm exceeding the negative electrode sheet is connected to the rubber coating member.

[0005] Optionally, the width of the positive electrode sheet is smaller than that of the negative electrode sheet, and the encapsulated component is connected to the outer surface of the positive electrode sheet.

[0006] Optionally, a positive electrode tab is led out from the positive electrode sheet at the top of the bare battery cell, a negative electrode tab is led out from the negative electrode sheet at the top of the bare battery cell, an insulating sheet is arranged on the top of the bare battery cell to separate the positive electrode tab from the negative electrode tab, and a fixing component connected to the rubber-coated part is arranged on the insulating sheet so that the top of the diaphragm can be fixed by rubber bundling through the fixing component.

[0007] Optionally, the fixing assembly includes a first fixing member and a second fixing member, the first fixing member is close to the negative electrode tab, and the first fixing member fixes the diaphragm at the negative electrode tab with glue, and the second fixing member is located in the middle of the insulating sheet, and the second fixing member fixes the insulating sheet and the diaphragm with glue.

[0008] Optionally, a top glue injection hole is provided in the middle of the insulating sheet, and the second fixing members are respectively provided at both ends of the top glue injection hole.

[0009] Optionally, the distance between the first fixing member and the negative electrode tab is in the range of 1 mm to 2 mm, and the distance between the second fixing member and the top glue injection hole is in the range of 0.5 mm to 1 mm.

[0010] Optionally, the first fixing member and the second fixing member are both rubber strips, and two ends of the rubber strips are respectively connected to two opposite side surfaces of the rubber-wrapped member.

[0011] Optionally, a third fixing member connected to the rubber-coated member is provided at the bottom of the bare cell, and the third fixing member is used to fix the bottom of the diaphragm by rubber bundling.

[0012] Optionally, the width of one side of the separator is greater than that of the negative electrode sheet by 0.5 mm to 1 mm.

[0013] The utility model also provides a power battery, comprising the above-mentioned battery cell.

[0014] Compared with the prior art, the battery cell and power battery provided by the embodiment of the utility model have the following beneficial effects:

[0015] In order to ensure that the diaphragm can separate the positive and negative electrodes of the bare cell, the width of the diaphragm of the bare cell is designed to be larger than the width of the negative electrode, and a rubber coating is provided on the surface of the bare cell so that the portion of the diaphragm extending beyond the negative electrode is connected to the rubber coating, thereby fixing the outermost positive electrode and diaphragm of the bare cell into one, so that the diaphragm between the positive and negative electrodes is not easy to slide. Furthermore, during the whole-machine testing of the battery, even if the bare cell collides with the shell, the connection between the diaphragm and the rubber coating limits the movement of the diaphragm, making it difficult for the diaphragm to slide, thereby avoiding micro-short circuits of the battery, thereby improving the reliability of the battery cell and the power battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The technical solution of the utility model will be further described in detail below with reference to the accompanying drawings and embodiments, in which:

[0017] Figure 1 A schematic diagram of the overall structure of a battery cell provided in an embodiment of the utility model;

[0018] Figure 2 A schematic diagram of an exploded structure of a battery cell provided in an embodiment of the utility model;

[0019] Figure 3 A schematic structural diagram of the top of a battery cell provided in an embodiment of the utility model.

[0020] The reference numerals in the figures are:

[0021] 1. Bare battery cell; 2. Rubber-coated part; 3. Positive electrode tab; 4. Negative electrode tab; 5. Insulating sheet; 6. First fixing part; 7. Second fixing part; 8. Top glue injection hole; 9. Third fixing part. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Now, in conjunction with the accompanying drawings, a preferred embodiment of the present utility model is described in detail.

[0023] The utility model embodiment provides a battery cell, such as Figure 1 and Figure 2 As shown, it includes a bare battery cell 1 and a rubber coating 2 covering the outer surface of the bare battery cell 1. The bare battery cell 1 includes a positive electrode sheet, a negative electrode sheet, and a diaphragm separating the positive electrode sheet and the negative electrode sheet, the width of the diaphragm is greater than the width of the negative electrode sheet, and the portion of the diaphragm exceeding the negative electrode sheet is connected to the rubber coating 2. Through the setting of this structure, the width of the diaphragm of the bare battery cell 1 is designed to be greater than the width of the negative electrode sheet to ensure that the diaphragm can separate the positive electrode sheet and the negative electrode sheet, and the rubber coating 2 covering the surface of the bare battery cell 1 is used to connect the portion of the diaphragm exceeding the negative electrode sheet to the rubber coating 2, so that the outermost electrode sheet and the diaphragm of the bare battery cell 1 are fixed as a whole, so as to ensure that during the collision between the bare battery cell 1 and the shell, the diaphragm between the positive electrode sheet and the negative electrode sheet is not easy to slide, thereby improving the reliability of the battery cell. The battery cell of this embodiment can be applied to electric vehicles, electronic consumer products, and home appliances.

[0024] Preferably, the rubber coating 2 can be made of a polymer material film having good insulation performance, chemical stability and mechanical strength, such as polyethylene, polyvinyl alcohol, polyimide (PI) and the like.

[0025] Furthermore, the positive electrode sheet is stacked or wound on the outer surface of the negative electrode sheet, and the width of the positive electrode sheet is smaller than that of the negative electrode sheet, and the rubber coating 2 is connected to the outer surface of the positive electrode sheet. Through the arrangement of this structure, in order to ensure that the battery has high capacity, low internal resistance and long life, the width of the positive electrode sheet is usually designed to be smaller than the width of the negative electrode sheet. Based on the battery cell structure, the rubber coating 2 is bonded to the outermost positive electrode sheet to fix the rubber coating 2, and the portion of the rubber coating 2 that exceeds the positive electrode sheet can be directly bonded to the diaphragm to further improve the degree of fixation of the diaphragm. At the same time, the width of the rubber coating 2 is greater than or equal to the width of the diaphragm, so that the portion of the diaphragm that exceeds the negative electrode sheet is connected to the rubber coating 2, thereby fixing the outermost positive electrode sheet and the diaphragm of the bare battery cell 1 into one, to ensure that the diaphragm is not easy to slide.

[0026] Furthermore, a positive electrode tab 3 is led out from the top of the bare cell 1 on the positive electrode sheet, and a negative electrode tab 4 is led out from the top of the bare cell 1 on the negative electrode sheet. An insulating sheet 5 is provided on the top of the bare cell 1 to separate the positive electrode tab 3 from the negative electrode tab 4. A fixing component connected to the rubber package 2 is provided on the insulating sheet 5 to fix the top of the diaphragm with rubber through the fixing component. Through the setting of this structure, in order to avoid the positive electrode tab 3 and the negative electrode tab 4 on the bare cell 1 from touching each other and short-circuiting, the positive electrode tab 3 and the negative electrode tab 4 of the bare cell 1 are effectively separated by the insulating sheet 5. Based on the setting of this structure, the top of the diaphragm is fixed with rubber using the fixing component on the insulating sheet 5 to avoid the top of the diaphragm being squeezed by the negative electrode tab 4 and the insulating sheet 5 during the top-bottom drop test of the battery, thereby preventing the top of the diaphragm from sliding due to the squeezing of the negative electrode tab 4 and the insulating sheet 5, thereby causing a micro-short circuit in the battery.

[0027] Further, the fixing assembly includes a first fixing member 6 and a second fixing member 7. The first fixing member 6 is close to the negative electrode tab 4, and the first fixing member 6 fixes the diaphragm at the negative electrode tab 4 by bundling with glue. The second fixing member 7 is located in the middle of the insulating sheet 5, and the second fixing member 7 fixes the insulating sheet 5 and the diaphragm by bundling with glue. Through the setting of this structure, since the negative electrode tab 4 is usually long and will be bent, when the bare battery cell 1 collides with the shell, the negative electrode tab 4 will continuously squeeze the diaphragm at the top of the bare battery cell 1, so that the diaphragm at this position is easy to slide, thereby causing the positive electrode sheet and the negative electrode sheet at this position to contact easily and form a micro short circuit. Therefore, this embodiment uses the first fixing member 6 adjacent to the negative electrode tab 4 to fix the diaphragm at the negative electrode tab 4 by bundling with glue, so that when the negative electrode tab 4 is constantly squeezing the diaphragm at the top of the bare battery cell 1, the diaphragm at this position is not easy to slide, thereby avoiding the situation where the positive electrode sheet and the negative electrode sheet at this position do not contact and cause a micro short circuit. At the same time, the insulating sheet 5 can be further fixed on the top of the bare cell 1 by the first fixing member 6 and the second fixing member 7, and the insulating sheet 5 and the diaphragm are glued and fixed by the second fixing member 7, so that the insulating sheet 5 is not easy to squeeze the diaphragm on the top of the bare cell 1.

[0028] Furthermore, combined with Figure 3 As shown, a top glue injection hole 8 is provided in the middle of the insulating sheet 5, and second fixing members 7 are provided at both ends of the top glue injection hole 8. Through the setting of this structure, a top glue injection hole 8 is provided in the middle of the insulating sheet 5, and the top glue injection hole 8 can be used to conveniently inject glue into the top of the bare battery cell 1, so as to fix and encapsulate the top of the bare battery cell 1 when encapsulating the battery cell. At the same time, since the insulating sheet 5 is only fixed by the second fixing member 7 during the collision between the bare battery cell 1 and the shell, the insulating sheet 5 on the top of the bare battery cell 1 is prone to unbalanced force, thereby squeezing the diaphragm, causing the diaphragm to slide easily, and then causing the positive electrode sheet and the negative electrode sheet at this position to contact easily and form a micro short circuit. Therefore, in this embodiment, a second fixing member 7 is respectively provided at both ends of the top glue injection hole 8, so that one of the second fixing members 7 is close to the negative electrode tab 4, and the other second fixing member 7 is close to the positive electrode tab 3, so that when the bare battery cell 1 collides with the shell, the insulating sheet 5 on the top of the bare battery cell 1 is subjected to balanced force, thereby avoiding the situation where the positive and negative electrode sheets at this position will not contact each other and cause a micro short circuit.

[0029] As described above, preferably, the distance between the first fixing member 6 and the negative electrode tab 4 is in the range of 1 mm to 2 mm, and the distance between the second fixing member 7 and the top glue injection hole 8 is in the range of 0.5 mm to 1 mm.

[0030] Furthermore, the first fixing member 6 and the second fixing member 7 are both rubber bands, and the two ends of the rubber bands are respectively connected to the two opposite side surfaces of the rubber-coated member 2. Through the arrangement of this structure, the diaphragm on the top of the bare cell 1 is tightly fixed by using the first fixing member 6 and the second fixing member 7 in a rubber-bundling manner, so as to prevent the negative electrode sheet and the insulating sheet 5 on the top of the bare cell 1 from squeezing the diaphragm on the top of the bare cell 1 during the whole-machine drop test of the battery, so that the diaphragm on the top of the bare cell 1 is not easy to slide, which helps to improve the stability of the cell, prevent the displacement or deformation of the internal components, and maintain the normal working state of the cell.

[0031] Furthermore, a third fixing member 9 connected to the rubber-encapsulating member 2 is provided at the bottom of the bare cell 1, and the third fixing member 9 is used to fix the bottom of the diaphragm with rubber. Through the setting of this structure, the diaphragm at the bottom of the bare cell 1 is fixed and encapsulated by the third fixing member 9, so that when the bare cell 1 collides with the shell, the diaphragm at the bottom of the bare cell 1 is not easy to slide, thereby avoiding the situation where the positive and negative electrodes at this position do not contact each other and cause a micro short circuit.

[0032] Preferably, the width of one side of the separator is greater than that of the negative electrode sheet by 0.5 mm to 1 mm.

[0033] The utility model also provides a power battery, comprising the above-mentioned battery cell.

[0034] In the battery cell and power battery of the utility model, in order to ensure that the diaphragm can separate the positive electrode sheet and the negative electrode sheet of the bare battery cell 1, the width of the diaphragm of the bare battery cell 1 is designed to be greater than the width of the negative electrode sheet, and a rubber coating 2 is provided on the surface of the bare battery cell 1 so that the portion of the diaphragm that exceeds the negative electrode sheet is connected to the rubber coating 2. At the same time, the width of the positive electrode sheet is designed to be smaller than the width of the negative electrode sheet so that the portion of the rubber coating 2 that exceeds the positive electrode sheet can be directly bonded to the diaphragm, thereby fixing the outermost positive electrode sheet and the diaphragm of the bare battery cell 1 into one body, so that the diaphragm between the positive electrode sheet and the negative electrode sheet is not easy to slide. In addition, by setting the first fixing member 6 and the second fixing member 7 on the top of the bare battery cell 1, the diaphragm at the negative electrode tab 4 on the top of the bare battery cell 1 and the diaphragm at the insulating sheet 5 are fixed respectively, so that when the bare battery cell 1 collides with the shell, the negative electrode tab 4 and the insulating sheet 5 continuously squeeze the diaphragm on the top of the bare battery cell 1, and the diaphragm at the corresponding position is not easy to slide, thereby avoiding the situation where the positive and negative electrode sheets at the corresponding positions do not contact each other and cause a micro short circuit, so as to improve the reliability of the battery cell and the power battery.

[0035] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present utility model rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and all these modifications and replacements should fall within the scope of protection of the claims attached to the present utility model.

Claims

1. A battery cell, characterized in that: The battery cell includes a bare battery cell and a rubber coating covering the outer surface of the bare battery cell. The bare battery cell includes a positive electrode sheet, a negative electrode sheet, and a diaphragm separating the positive electrode sheet from the negative electrode sheet. The width of the diaphragm is greater than the width of the negative electrode sheet, and the portion of the diaphragm that exceeds the negative electrode sheet is connected to the rubber coating.

2. The battery cell according to claim 1, characterized in that: The width of the positive electrode sheet is smaller than that of the negative electrode sheet, and the encapsulated component is connected to the outer surface of the positive electrode sheet.

3. The battery cell according to claim 1 or 2, characterized in that: The positive electrode sheet is provided with a positive electrode tab at the top of the bare battery cell, the negative electrode sheet is provided with a negative electrode tab at the top of the bare battery cell, an insulating sheet is provided at the top of the bare battery cell to separate the positive electrode tab from the negative electrode tab, and a fixing component connected to the rubber-coated part is provided on the insulating sheet so that the top of the diaphragm can be fixed by rubber bundling through the fixing component.

4. The battery cell according to claim 3, characterized in that: The fixing assembly includes a first fixing member and a second fixing member, wherein the first fixing member is close to the negative electrode tab, and the first fixing member fixes the diaphragm at the negative electrode tab with glue, and the second fixing member is located in the middle of the insulating sheet, and the second fixing member fixes the insulating sheet and the diaphragm with glue.

5. The battery cell according to claim 4, characterized in that: A top glue injection hole is arranged in the middle of the insulating sheet, and the second fixing members are arranged at both ends of the top glue injection hole.

6. The battery cell according to claim 5, characterized in that: The distance between the first fixing member and the negative electrode tab is in the range of 1 mm to 2 mm, and the distance between the second fixing member and the top glue injection hole is in the range of 0.5 mm to 1 mm.

7. The battery cell according to claim 4 or 5, characterized in that: The first fixing member and the second fixing member are both rubber strips, and two ends of the rubber strips are respectively connected to two opposite side surfaces of the rubber-wrapped member.

8. The battery cell according to claim 1 or 6, characterized in that: A third fixing piece connected to the rubber-coated piece is provided at the bottom of the bare cell, and the third fixing piece is used to fix the bottom of the diaphragm by rubber bundling.

9. The battery cell according to claim 1, characterized in that: The width of one side of the separator is greater than that of the negative electrode sheet by 0.5 mm to 1 mm.

10. A power battery, characterized in that: The power battery comprises the battery cell according to any one of claims 1 to 9.

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