Battery pole piece, winding battery and electric equipment

Abstract

The invention belongs to the technical field of battery production, and discloses a battery pole piece, a winding battery and electric equipment. The battery pole piece comprises a pole piece body and a connecting tab, the pole piece body comprises a first active area and a second active area which are both coated with active substances, and the electrolyte storage capacity of the first active area is larger than that of the second active area; wherein in the length direction, the part, located in the center, of the wound pole piece body is a first end, the part, located on the periphery, of the wound pole piece body is a second end, the first active area is arranged at the first end, and the second active area is arranged at the second end; one end of the connecting tab is connected to the pole piece body, and the other end extends out of the pole piece body along the width direction. After the battery pole piece is formed into the winding battery, the electrolyte consumption of the central part is not faster than that of the peripheral part, so that the problem that the electrolyte consumption of the central part of the winding battery is too large is solved, the diving phenomenon of the winding battery is avoided, and the service life of the winding battery is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of battery production, and in particular to a battery pole piece, a wound battery and an electrical device. Background Art

[0002] Under normal cycling conditions, the lithium ions consumed by the growth and thickening of the solid electrolyte interface (SEI) on the surface of the negative electrode active material particles as the battery ages are the main cause of battery capacity decay. At this time, the battery capacity decays approximately linearly with the increase of the cumulative number of charge and discharge times, or the number of equivalent full charge and discharge cycles. In some cases, after a period of approximately linear decay, the battery may experience a sudden and rapid capacity decay, that is, a capacity "dive", which indicates that a new aging mechanism has emerged to dominate the battery capacity decay process. Normally used batteries will experience a diving phenomenon at the end of the cycle. This is because during the battery cycle, SEI repair and reorganization will continuously consume electrolyte. At the end of the cycle life, the electrolyte is exhausted, causing the battery to dive on a macro scale.

[0003] Currently, all existing pole pieces are coated with a slurry from the head to the tail of the pole piece. The type of active material on the pole piece is single and the physical and chemical properties are uniform. When making a wound battery, after the core is wound, although the material properties of the inner and outer rings of the core are the same, the inner ring of the core is subjected to a large extrusion pressure due to the winding structure, and it is more difficult for the inner ring to preserve the electrolyte. At the end of the battery cell cycle life, the consumption of electrolyte in the inner ring of the core is greater than that in the outer ring, and the electrolyte in the inner ring is consumed first, resulting in the problem of rapid deterioration of the battery cell capacity and internal resistance, causing a greatly increased risk of battery diving from the center.

[0004] Therefore, there is an urgent need to provide a new type of battery electrode, wound battery and electrical equipment to solve the above-mentioned technical problems in the prior art. Summary of the invention

[0005] The object of the present invention is to provide a battery pole piece, which can increase the electrolyte capacity of a wound battery, improve the problem of excessive electrolyte consumption in the center of the wound battery, avoid the phenomenon of water diving in the wound battery, and increase the service life of the wound battery.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] The battery electrode comprises a electrode body and a connecting electrode ear, wherein the length direction of the electrode body is the direction of winding to form a winding core, and the width direction of the electrode body is the height direction of the winding core, and the electrode body comprises a first active area and a second active area both coated with active materials, and the electrolyte storage capacity of the first active area is greater than the electrolyte storage capacity of the second active area; wherein, along the above-mentioned length direction, the portion located at the center after the above-mentioned electrode body is wound is the first end, and the portion located at the periphery after the above-mentioned electrode body is wound is the second end, the above-mentioned first active area is arranged at the above-mentioned first end, and the above-mentioned second active area is arranged at the above-mentioned second end; one end of the above-mentioned connecting electrode ear is connected to the above-mentioned electrode body, and the other end extends outwardly along the above-mentioned width direction to the outside of the above-mentioned electrode body.

[0008] Optionally, a dimension of the first active area along the length direction is not greater than a dimension of the second active area along the length direction.

[0009] Optionally, a dimension of the first active area along the length direction is not less than 1 / 3 of a dimension of the pole piece body along the length direction.

[0010] Optionally, the pole piece body comprises an empty foil area not coated with active material, the empty foil area is connected to the connecting electrode ear, and the dimension of the empty foil area along the width direction is equal to the dimension of the pole piece body along the width direction.

[0011] Optionally, the empty foil area is sandwiched between the first active area and the second active area.

[0012] Optionally, there are two empty foil areas and they are located at both ends of the pole piece body along the length direction; or there are two empty foil areas and they are respectively arranged in one-to-one correspondence at the first active area and the second active area.

[0013] Optionally, one end of the pole piece body along the width direction is provided with a coating area for coating the active material, and the other end is a blank area, the coating area includes the first active area and the second active area, and the connecting pole ear includes the blank area.

[0014] Optionally, the porosity of the active material in the first active area is greater than the porosity of the active material in the second active area.

[0015] Another object of the present invention is to provide a wound battery, which includes the battery pole piece described in any of the above schemes.

[0016] Another object of the present invention is to provide an electrical device, which comprises the wound battery as described in the above solution.

[0017] Beneficial effects:

[0018] The battery pole piece in the present invention has a connecting pole ear connected to the pole piece body, and the pole piece body is coated with active material in different areas, including a first active area coated on the first end and a second active area coated on the second end. The first end is the central part of the winding core, and the second end is the peripheral part of the winding core. The electrolyte storage capacity of the first active area is greater than the electrolyte storage capacity of the second active area, so that after the battery pole piece is wound to form the winding core, the electrolyte storage capacity of the central part is greater than the electrolyte storage capacity of the peripheral part. After forming a wound battery, the electrolyte consumption of the central part will not be faster than that of the peripheral part, so that the wound battery improves the problem of excessive electrolyte consumption in the central part, avoids the diving phenomenon of the wound battery, and improves the service life of the wound battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of a battery electrode in Example 1 provided in a specific embodiment of the present invention;

[0020] Figure 2 is a schematic diagram of a battery electrode in Example 2 provided in a specific embodiment of the present invention;

[0021] Figure 3 It is a schematic diagram of a battery electrode in Example 3 provided in a specific implementation manner of the present invention;

[0022] Figure 4 It is a schematic diagram of the battery electrode in Example 4 provided in the specific implementation manner of the present invention.

[0023] In the figure:

[0024] 100, pole piece body; 101, first end; 102, second end; 110, first active area; 120, second active area; 130, empty foil area; 200, connecting pole ear. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0026] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0028] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0029] like Figures 1 to 4 As shown, the battery electrode in this embodiment includes a positive electrode and a negative electrode. Figures 1 to 4 In each figure, the one located on the top is the positive electrode sheet, and the one located on the bottom is the negative electrode sheet. The positive electrode sheet and the negative electrode sheet are stacked and wound to form a roll core.

[0030] Embodiment 1

[0031] like Figure 1 As shown, the battery electrode includes a electrode body 100 and a connecting electrode ear 200, the length direction of the electrode body 100 is the direction of winding to form a winding core, the width direction of the electrode body 100 is the height direction of the winding core, the electrode body 100 includes a first active area 110 and a second active area 120 both coated with active materials, the electrolyte storage capacity of the first active area 110 is greater than the electrolyte storage capacity of the second active area 120; wherein, along the above-mentioned length direction, the portion located at the center of the above-mentioned electrode body 100 after winding is the first end 101, and the portion located at the periphery of the above-mentioned electrode body 100 after winding is the second end 102, the above-mentioned first active area 110 is arranged at the above-mentioned first end 101, and the above-mentioned second active area 120 is arranged at the above-mentioned second end 102; one end of the above-mentioned connecting electrode ear 200 is connected to the above-mentioned electrode body 100, and the other end extends outside the above-mentioned electrode body 100 along the above-mentioned width direction.

[0032] The battery electrode in this embodiment has a connecting ear 200 connected to the electrode body 100, and the electrode body 100 is coated with active material in different areas, including a first active area 110 coated on the first end 101 and a second active area 120 coated on the second end 102. The first end 101 is the central part of the winding core, and the second end 102 is the peripheral part of the winding core. The electrolyte storage capacity of the first active area 110 is greater than the electrolyte storage capacity of the second active area 120, so that after the battery electrode is wound to form a winding core, the electrolyte storage capacity of the central part is greater than the electrolyte storage capacity of the peripheral part. After forming a wound battery, the electrolyte consumption of the central part will not be faster than that of the peripheral part, so that the wound battery improves the problem of excessive electrolyte consumption in the central part, avoids the diving phenomenon of the wound battery, and improves the service life of the wound battery.

[0033] In this embodiment, the dimension of the first active area 110 along the length direction is not greater than the dimension of the second active area 120 along the length direction. That is, the length of the first active area 110 does not exceed 1 / 2 of the length of the electrode body 100. This is because when the battery electrode is wound, the diameter of the winding gradually increases from the inside to the outside, and the length of the battery electrode required in the center will not exceed the length of the battery electrode at the periphery. Therefore, the function of increasing the electrolyte capacity in the center can be achieved by only setting the length of the first active area 110 not to exceed that of the second active area 120.

[0034] Furthermore, the dimension of the first active area 110 along the length direction is not less than 1 / 3 of the dimension of the pole piece body 100 along the length direction. That is, the length of the first active area 110 is 1 / 3 to 1 / 2 of the length of the pole piece body 100. Such a setting can ensure that the first active area 110 has sufficient length to increase the capacity of the electrolyte in the center, and the wall wound battery has no diving phenomenon, thereby improving the service life of the wound battery.

[0035] Specifically, in this embodiment, the length of the first active area 110 is 1 / 3 of the length of the pole piece body 100 , which will not be described in detail here.

[0036] Optionally, the pole piece body 100 includes an empty foil area 130 not coated with active material, the empty foil area 130 is connected to the connecting tab 200, and the size of the empty foil area 130 along the width direction is equal to the size of the pole piece body 100 along the width direction. Figure 1 As shown in the positive electrode sheet in the upper middle, the empty foil area 130 is used to fix the connection tab 200 to achieve the external discharge of the winding core; Figure 1As shown in the negative electrode sheet in the lower middle, in addition to the empty foil area 130 for fixing the connecting tab 200, empty foil areas 130 are also provided at both ends of the electrode body 100 of the negative electrode sheet, which are used to unify and align the lengths of the active areas on the positive and negative electrode sheets during winding, which will not be repeated here.

[0037] Specifically, the above-mentioned empty foil area 130 is sandwiched between the above-mentioned first active area 110 and the above-mentioned second active area 120. Such a setting is applicable to a single-pole winding battery cell, which will not be described in detail here.

[0038] Optionally, the porosity of the active material in the first active area 110 is greater than the porosity of the active material in the second active area 120. In this embodiment, the active materials coated on the first active area 110 and the second active area 120 are different, and specifically, the porosity of the material in the first active area 110 is larger, so it can accommodate more electrolyte; the first active area 110 and the second active area 120 are coated in different regions using a dual-die coating, and the dual-die is used to coat active materials of different materials, which will not be described in detail here.

[0039] Embodiment 2

[0040] like Figure 2 As shown, the only difference from the first embodiment is that Figure 2 In the negative electrode sheet located at the bottom, the above-mentioned empty foil area 130 is provided with two and is located at the two ends of the above-mentioned electrode body 100 along the above-mentioned length direction; in this way, a multi-pole winding cell structure with a single positive electrode ear and a double negative electrode ear can be realized, thereby improving the charge and discharge rate of the wound battery, which will not be repeated here.

[0041] Furthermore, in this embodiment, the length of the first active area 110 is 1 / 2 of the length of the pole piece body 100 , which will not be described in detail here.

[0042] Embodiment 3

[0043] like Figure 3 As shown, the difference from the above-mentioned embodiment 2 is that: Figure 3 In the positive electrode sheet located at the top, two empty foil areas 130 are provided, and the two empty foil areas 130 are respectively provided in the first active area 110 and the second active area 120 in a one-to-one correspondence. In this way, a wound battery cell with a bipolar ear structure in which both the positive electrode sheet and the negative electrode sheet are wound can be realized, further improving the charge and discharge rate of the wound battery.

[0044] Embodiment 4

[0045] like Figure 4As shown, the difference from the above-mentioned embodiment 1 is that the winding core formed by winding the battery pole piece in this embodiment is a full-ear structure, and the pole piece body 100 is provided with a coating area for coating the above-mentioned active material at one end along the above-mentioned width direction, and the other end is a blank area, and the above-mentioned coating area includes the above-mentioned first active area 110 and the above-mentioned second active area 120, and the above-mentioned connecting pole ear 200 includes the above-mentioned blank area. Specifically, the above-mentioned connecting pole ear 200 is provided at any end of the above-mentioned pole piece body 100 along the above-mentioned width direction, and the above-mentioned connecting pole ear 200 and the above-mentioned pole piece body 100 are arranged end to end in the length direction, that is, the size of the connecting pole ear 200 along the above-mentioned length direction is the same as the size of the above-mentioned pole piece body 100 along the above-mentioned length direction. The wound battery formed by the full-ear winding battery core directly draws current from the current collectors on the positive and negative pole pieces, thereby greatly increasing the current path and shortening the spacing of the connecting pole ears 200, thereby greatly improving the battery power.

[0046] The following table introduces the comparison between the cycle life of the battery electrode sheet in this embodiment formed into a wound battery and the cycle life of the original wound battery.

[0047]

[0048] It can be seen that for battery electrodes made of a single active material, setting a first active area 110 with a length of 1 / 3 to 1 / 2 at the first end 101 of the electrode body 100 can improve the cycle life of the wound battery; while setting the entire electrode body 100 to be a high-porosity material has limited improvement, and the cycle life is not as good as setting the first active area 110 in the front 1 / 3 of the electrode body 100.

[0049] This embodiment also provides a wound battery, which includes the battery pole piece described in any of the above schemes. The wound battery can specifically be a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid (or lead storage) battery, a lithium-ion battery, a polymer lithium-ion battery, etc. The wound battery can also be a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery or a sodium-ion battery or a magnesium-ion battery, etc., which will not be repeated here. The wound battery has the beneficial effects of the battery pole piece described in any of the above schemes, which will not be repeated here.

[0050] Specifically, when the wound battery uses the above-mentioned battery electrode, the electrolyte storage capacity in the central part of the internal winding core is greater than the electrolyte storage capacity in the peripheral part, and the electrolyte consumption in the central part will not be faster than that in the peripheral part, so that the wound battery can improve the problem of excessive electrolyte consumption in the central part, avoid the phenomenon of water diving in the wound battery, and increase the service life of the wound battery.

[0051] This embodiment further provides an electric device, which includes the wound battery as described in the above solution. The electric device can be an electric bicycle, an electric car, a hybrid car, a ship, an energy storage device, etc., as long as it uses electric energy as an energy source, which will not be described in detail here.

[0052] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A battery pole piece, characterized in that: include: A pole piece body, wherein the length direction of the pole piece body is the direction of winding to form a winding core, the width direction of the pole piece body is the height direction of the winding core, the pole piece body comprises a first active area and a second active area both coated with active materials, the electrolyte storage capacity of the first active area is greater than the electrolyte storage capacity of the second active area; wherein, along the length direction, the portion of the pole piece body located at the center after winding is the first end, and the portion of the pole piece body located at the periphery after winding is the second end, the first active area is arranged at the first end, and the second active area is arranged at the second end; A connecting pole ear, one end of which is connected to the pole piece body, and the other end of which extends outwardly along the width direction to the outside of the pole piece body.

2. The battery electrode according to claim 1, characterized in that: A dimension of the first active area along the length direction is not greater than a dimension of the second active area along the length direction.

3. The battery pole piece according to claim 2, characterized in that: The dimension of the first active area along the length direction is not less than 1 / 3 of the dimension of the pole piece body along the length direction.

4. The battery pole piece according to claim 1, characterized in that: The pole piece body comprises an empty foil area which is not coated with active material, the empty foil area is connected to the connecting electrode ear, and the dimension of the empty foil area along the width direction is equal to the dimension of the pole piece body along the width direction.

5. The battery pole piece according to claim 4, characterized in that: The empty foil area is sandwiched between the first active area and the second active area.

6. The battery pole piece according to claim 4, characterized in that: There are two empty foil areas and they are located at two ends of the pole piece body along the length direction; or there are two empty foil areas and they are respectively arranged in one-to-one correspondence at the first active area and the second active area.

7. The battery pole piece according to any one of claims 1 to 6, characterized in that: One end of the pole piece body along the width direction is provided with a coating area for coating the active material, and the other end is a blank area, the coating area includes the first active area and the second active area, and the connecting tab includes the blank area.

8. The battery pole piece according to any one of claims 1 to 6, characterized in that: The porosity of the active material in the first active area is greater than the porosity of the active material in the second active area.

9. A wound battery, characterized in that Comprising the battery pole piece as described in any one of claims 1-8.

10. Electrical equipment, characterized in that: Comprising the wound battery as claimed in claim 9.

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