Battery assembly and vehicle

Abstract

The utility model discloses a battery assembly and a vehicle, the battery assembly comprises a diaphragm, a pole piece and a filling piece, the pole piece is arranged on one side of the diaphragm in the thickness direction, a thinning area is formed on the edge of the pole piece, and a gap is formed between the thinning area and the diaphragm; the filling piece is arranged at the edge of the pole piece and at least part of the filling piece is filled into the gap. According to the battery assembly provided by the utility model, the gap is filled with at least part of the filling piece, so that the polarization effect can be reduced, lithium precipitation is inhibited, and the reliability of the battery is improved.

Description

Technical Field

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

[0002] With the increasing demand for environmental protection and sustainable energy in modern society, electric vehicles and portable electronic devices have been widely used. As an energy storage unit, the cycle performance of lithium batteries is of great significance to the stability and life of the equipment.

[0003] Existing lithium battery designs use an extrusion coating process during manufacturing, which results in a thinned area at the edge of the pole piece. The distance between the positive and negative electrodes in the thinned area is larger than that in the main body, which increases the polarization effect and electrolyte side reactions, leading to electrolyte drying up, and problems such as edge lithium deposition and diaphragm puncture under long cycle conditions, causing thermal runaway of the battery cell. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the utility model is to provide a battery assembly. According to the battery assembly of the utility model, by filling at least part of the filler into the gap, the polarization effect can be reduced, lithium plating can be suppressed, and the reliability of the battery can be improved.

[0005] The utility model also provides a vehicle with the battery assembly.

[0006] The battery assembly according to the utility model comprises: a diaphragm; a pole piece, which is arranged on one side of the diaphragm in the thickness direction, and the pole piece is provided with a thinning area so that a gap is formed between the pole piece and the diaphragm; and a filling piece, at least a part of which is filled into the gap.

[0007] According to the battery assembly of the utility model, the pole piece is responsible for the storage and release of electric energy. By setting a diaphragm, the pole piece is set on one side in the thickness direction of the diaphragm, and the diaphragm separates the positive and negative electrodes of the battery to prevent short circuits and keep the battery running safely. Since the pole piece is formed with a thinning area, a gap is formed between the thinning area and the diaphragm. By filling at least part of the filler into the gap, the polarization effect can be reduced, lithium precipitation at the edge of the pole piece can be suppressed, and the reliability of the battery can be improved.

[0008] In particular, during the cell formation process, the battery assembly will generate heat, and the filler will expand in volume when heated and in contact with the electrolyte, further filling the gap. After expansion, abundant tiny pores are formed inside the filler, and the pores can effectively store the electrolyte. During the battery charging process, the negative electrode sheet expands, the total volume of the pores of the sheet increases, the filler is squeezed by the negative electrode sheet, the electrolyte inside the filler is squeezed out, and fills the pores of the negative electrode sheet. When the battery is discharged, the negative electrode sheet shrinks, and the volume of the porosity filler is restored. The filler can absorb the electrolyte squeezed out due to the reduction of the pores of the negative electrode sheet. The electrode sheet is completely immersed in the electrolyte during the charging and discharging process, reducing side reactions and improving the performance of the battery assembly.

[0009] According to some embodiments of the utility model, a thinned area is provided on the edge of the pole piece in the length direction.

[0010] According to some embodiments of the present invention, the filling member includes: a first filling portion, which is arranged in the gap; and a second filling portion, which is located on a side of the first filling portion away from the pole piece.

[0011] According to some embodiments of the present invention, the thickness of the gap gradually increases in the length direction away from the pole piece; the thickness of the first filling portion gradually increases in the length direction away from the pole piece.

[0012] According to some embodiments of the present invention, the filling member further includes: an adhesive layer, wherein the adhesive layer is respectively arranged between the first filling part and the diaphragm, and between the second filling part and the diaphragm.

[0013] According to some embodiments of the present invention, the length of the first filling portion is n, the length of the gap is L and they satisfy: 0.6≤n / L≤1.

[0014] According to some embodiments of the present invention, the maximum thickness of the first filling portion is a1, the thickness of the glue layer is b, the maximum thickness of the pole piece is c and satisfies: 0.6≤ / c≤1.

[0015] According to some embodiments of the present invention, the thickness of the second filling portion is a2, the expansion rate of the second filling portion is e, the thickness of the glue layer is b, the thickness of the pole piece is c and satisfies: 1≤ / c≤1.05.

[0016] According to some embodiments of the utility model, the electrode sheets include a positive electrode sheet and a negative electrode sheet, one of the positive electrode sheet or the negative electrode sheet is arranged between two adjacent diaphragms, and the thinned area of ​​the positive electrode sheet and the thinned area of ​​the negative electrode sheet are located on the same side or different sides of the battery assembly.

[0017] The vehicle according to the present utility model is briefly described below.

[0018] The vehicle according to the utility model includes the battery assembly described in any one of the above embodiments. Since the vehicle according to the utility model includes the battery assembly described in any one of the above embodiments, the vehicle according to the utility model has higher reliability, higher endurance and better performance by adopting a high-performance and high-reliability battery assembly.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0021] Figure 1 It is a schematic diagram of a battery assembly at the edge of a pole piece according to an embodiment of the utility model;

[0022] Figure 2 is a cross-sectional view of a battery assembly in the length direction according to an embodiment of the utility model;

[0023] Figure 3 is a cross-sectional view of a battery assembly in the length direction according to another embodiment of the utility model;

[0024] Figure 4 is a cross-sectional view of a first filling portion according to an embodiment of the present utility model, in which the cross-sectional shape in the thickness direction is an arc shape;

[0025] Figure 5 is a cross-sectional view of a first filling portion according to an embodiment of the utility model, in which the cross-sectional shape in the thickness direction is a stepped shape;

[0026] Figure 6 is a cross-sectional view of a first filling portion according to an embodiment of the present utility model, in which the cross-sectional shape in the thickness direction is a triangle;

[0027] Figure 7 is a cross-sectional view of a first filling portion according to an embodiment of the utility model, in which the cross-sectional shape in the thickness direction is a trapezoid;

[0028] Figure 8 is a schematic diagram of a battery assembly according to an embodiment of the utility model being a laminated battery;

[0029] Fig. 9 The battery assembly according to one embodiment of the utility model is a cross-sectional view in the width direction of a wound battery.

[0030] Reference numerals:

[0031] Battery assembly 1;

[0032] Diaphragm 11;

[0033] Pole piece 12, thinned area 12a, positive pole piece 121, negative pole piece 122;

[0034] The filling piece 13 comprises a first filling portion 131 and a second filling portion 132 . DETAILED DESCRIPTION

[0035] The embodiments of the present invention are described in detail below, and 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 only used to explain the present invention, and cannot be understood as limiting the present invention.

[0036] In the related technology, the existing lithium battery design adopts the extrusion coating process during the manufacturing process, which leads to the thinning area at the edge of the pole piece. The distance between the positive and negative electrodes in the thinning area is larger than the main part, which increases the polarization effect and electrolyte side reactions, causing the electrolyte to dry up, and under long-cycle conditions, problems such as edge lithium deposition and diaphragm puncture occur, causing thermal runaway of the battery cell.

[0037] Reference below Figure 1-Figure 5 A battery assembly according to an embodiment of the present invention is described.

[0038] According to the utility model, the battery assembly includes a diaphragm, a pole piece and a filling piece. The pole piece is arranged on one side in the thickness direction of the diaphragm, a thinning area is formed at the edge of the pole piece, and a gap is formed between the thinning area and the diaphragm; the filling piece is arranged at the edge of the pole piece and at least part of the filling piece is filled into the gap.

[0039] Reference below Figure 1-Figure 9 A battery assembly 1 according to an embodiment of the present invention is described.

[0040] like Figure 1-Figure 3 As shown, the battery assembly 1 according to the utility model includes a diaphragm 11, a pole piece 12 and a filling piece 13. The pole piece 12 is arranged on one side of the diaphragm 11 in the thickness direction. The pole piece 12 is provided with a thinning area so that a gap is formed between the pole piece 12 and the diaphragm 11; at least a portion of the filling piece 13 is filled into the gap.

[0041] In the battery assembly 1 of the present application, the pole piece 12 is responsible for the storage and release of electric energy. By setting the diaphragm 11, the pole piece 12 is set on one side in the thickness direction of the diaphragm 11. The diaphragm 11 separates the positive and negative electrodes of the battery to prevent short circuits and keep the battery running safely. Since the pole piece 12 is formed with a thinned area 12a, a gap is formed between the thinned area 12a and the diaphragm 11. By filling at least part of the filler 13 into the gap, the polarization effect can be reduced, lithium precipitation can be suppressed, and the reliability of the battery can be improved.

[0042] In particular, during the cell formation process, the battery assembly 1 generates heat, and the filler 13 expands in volume when heated and encountering electrolyte, further filling the gap. After expansion, abundant tiny pores are formed inside the filler 13, and the pores can effectively store electrolyte. During the battery charging process, the negative electrode plate 122 expands, resulting in an increase in the total pore volume of the negative electrode plate 122. The filler 13 is squeezed by the negative electrode plate, and the electrolyte inside the filler 13 is squeezed out and fills the pores of the negative electrode plate 122. When the battery is discharged, the negative electrode plate 122 shrinks, and the volume of the filler 13 is restored. The filler 13 can absorb the electrolyte squeezed out due to the reduction in the pore volume of the negative electrode plate, so that the plate 12 is completely immersed in the electrolyte during the charge and discharge overcharge, reducing side reactions and improving the performance of the battery assembly 1.

[0043] Therefore, the battery assembly 1 of the present application can reduce the polarization effect, inhibit lithium deposition at the edge of the pole piece 12, and improve the reliability of the battery by filling at least part of the filler 13 into the gap.

[0044] According to some embodiments of the present invention, Figure 1-Figure 3 As shown, the pole piece 12 is provided with a thinning zone at the edge in the length direction. Since the battery assembly 1 is manufactured by an extrusion coating process, a thinning zone is formed at the edge of the pole piece 12. Due to the existence of the thinning zone, the spacing between the positive pole piece and the negative pole piece will increase at the thinning zone. Therefore, by filling at least part of the filler 13 into the gap, the polarization effect can be reduced, lithium deposition at the edge of the pole piece 12 can be suppressed, and the reliability of the battery can be improved.

[0045] According to some embodiments of the present invention, Figure 1-Figure 3 As shown, the filler 13 includes a first filling portion 131 and a second filling portion 132, wherein the first filling portion 131 is disposed in the gap; and the second filling portion 132 is located on the side of the first filling portion 131 away from the pole piece 12. By disposing the first filling portion 131 in the gap, the first filling portion 131 can fill the gap, thereby reducing the polarization effect. By disposing the second filling portion 132 on the side of the first filling portion 131 away from the pole piece 12, the second filling portion 132 can store electrolyte after expansion, reduce side reactions, and improve the stability and reliability of the battery assembly 1.

[0046] According to some embodiments of the present invention, Figure 1-Figure 3 As shown, the thickness of the gap gradually increases in the length direction away from the pole piece 12; the thickness of the first filling portion 131 gradually increases in the edge direction away from the pole piece 12. Since the thickness of the gap gradually increases, by configuring the first filling portion 131 to have a thickness gradually increasing in the edge direction away from the pole piece 12, a better filling effect can be achieved, and the first filling portion 131 can better adapt to the change of the gap and more effectively reduce the polarization effect.

[0047] According to some embodiments of the present invention, the cross-sectional shape of the first filling portion 131 in the thickness direction may be triangular, trapezoidal, arc-shaped, or stepped. Figure 4 As shown, the cross-sectional shape of the first filling portion 131 in the thickness direction is an arc shape. Figure 5 As shown, the cross-sectional shape of the first filling portion 131 in the thickness direction is a step shape. Figure 6 As shown, the cross-sectional shape of the first filling portion 131 in the thickness direction is a triangle. Figure 7 As shown, the cross-sectional shape of the first filling portion 131 in the thickness direction is a trapezoid.

[0048] According to some embodiments of the utility model, the filling member 13 further includes an adhesive layer, which is respectively arranged between the first filling portion 131 and the diaphragm 11, and between the second filling portion 132 and the diaphragm 11. By arranging the adhesive layer, the adhesive layer can play a bonding role, and the first filling portion 131 and the second filling portion 132 can be firmly fixed on the diaphragm 11, which can enhance the connection strength between the filling member 13 and the diaphragm 11 and improve stability. Specifically, the adhesive layer can be made of a material with good bonding properties, such as polyacrylate. The setting of the adhesive layer can be achieved by coating, so that the adhesive layer can evenly cover the contact surfaces between the first filling portion 131 and the second filling portion 132 and the diaphragm 11, respectively.

[0049] According to some embodiments of the present invention, the length of the first filling portion 131 is n, the length of the gap is L and satisfies: 0.6≤n / L≤1. The length of the first filling portion 131 refers to the length of the first filling portion 131 when it is not expanded. By controlling the ratio of the length of the first filling portion 131 to the length of the gap to be between 0.6 and 1, the first filling portion 131 can fully cover the thinned area 12a at the edge of the pole piece 12 in the length direction when expanded, which can effectively reduce the polarization effect.

[0050] According to some embodiments of the present invention, the maximum thickness of the first filling portion 131 is a1, the thickness of the glue layer is b, and the thickness of the pole piece 12 is c and satisfies: 0.6≤(a1+b) / c≤1. The maximum thickness of the first filling portion 131 refers to the maximum thickness of the first filling portion 131 when it is not expanded. By controlling the ratio of the total thickness of the first filling portion 131 and the glue layer to the thickness of the pole piece 12 to be between 0.6 and 1, the first filling portion 131 can fully cover the thinned area 12a at the edge of the pole piece 12 in the thickness direction when expanded, which can effectively reduce the polarization effect.

[0051] According to some embodiments of the utility model, the thickness of the second filling portion 132 is a2, the expansion rate of the second filling portion 132 is e, the thickness of the glue layer is b, the maximum thickness of the pole piece 12 is c and satisfies: 1≤(a2*e+b) / c≤1.05. The thickness of the second filling portion 132 refers to the thickness of the second filling portion 132 when it is not expanded. e refers to the expansion rate of the second filling portion 132. Generally speaking, e>150%. The expansion rate of the first filling portion 131 is the same. a2*e refers to the thickness of the second filling portion 132 after expansion, so a2*e+b refers to the thickness of the filler 13 after expansion at the second filling portion 132. The thickness of the pole piece 12 in the thinning area will decrease, and the maximum thickness of the pole piece 12 is the thickness of the pole piece 12 not in the thinning area 12a. By controlling the ratio of the thickness of the filler 13 after expansion at the second filling portion 132 to the thickness of the pole piece 12 to be between 1 and 1.05, the second filling portion 132 on one side of the pole piece 12 can fully absorb the electrolyte squeezed out of the pole piece 12, so that the pole piece 12 is completely immersed in the electrolyte during charge and discharge overcharge, effectively reducing side reactions and improving the performance of the battery assembly 1.

[0052] According to some embodiments of the present invention, Figure 2 and Figure 3As shown, the separator 11 is constructed into multiple pieces and is spaced apart in the thickness direction; the pole piece 12 is constructed into multiple pieces and is divided into a positive pole piece 121 and a negative pole piece 122. A positive pole piece 121 or a negative pole piece 122 is arranged between two adjacent separators 11, and the positive pole piece 121 and the negative pole piece 122 are arranged alternately in the thickness direction of the separator 11. By constructing the separator 11 into multiple pieces and spacing them in the thickness direction, a positive pole piece 121 or a negative pole piece 122 can be arranged between two adjacent separators 11, and ions are transmitted between the positive pole piece 121 and the negative pole piece 122 to realize the charging and discharging process of the battery, so the battery assembly 1 can accommodate more active materials and increase the energy storage capacity of the battery. By arranging the positive pole piece 121 and the negative pole piece 122 alternately in the thickness direction of the separator 11, a more uniform current distribution can be achieved. Since the positive electrode sheet 121 and the negative electrode sheet 122 are respectively located on both sides of the diaphragm 11, when the battery is charged and discharged, the current will flow along the thickness direction of the diaphragm 11. The diaphragm 11 separates the positive electrode sheet 121 and the negative electrode to prevent short circuit and keep the battery running safely.

[0053] According to some embodiments of the present invention, Figure 3 As shown, the thinned area 12a of the positive electrode sheet 121 and the thinned area 12a of the negative electrode sheet 122 are located on the same side of the battery assembly 1. By arranging the thinned area 12a of the positive electrode sheet 121 and the thinned area 12a of the negative electrode sheet 122 on the same side of the battery assembly 1, the positive electrode tab and the negative electrode tab of the battery assembly 1 are on the same side, which can simplify the circuit connection method and reduce the complexity of wiring.

[0054] According to some embodiments of the present invention, Figure 2 As shown, the thinned area 12a of the positive electrode sheet 121 and the thinned area 12a of the negative electrode sheet 122 are located on different sides of the battery assembly 1. By arranging the thinned area 12a of the positive electrode sheet 121 and the thinned area 12a of the negative electrode sheet 122 on different sides of the battery assembly 1, the positive electrode tab and the negative electrode tab of the battery assembly 1 are on different sides, which can meet the requirements of different application scenarios and reduce the risk of short circuit.

[0055] According to some embodiments of the present invention, Figure 8 As shown, the battery assembly 1 is constructed as a laminated battery. By constructing the battery assembly 1 as a laminated battery, the positive electrode sheet 121, the separator 11 and the negative electrode sheet 122 are stacked together in sequence and fixed together by welding or bonding, etc., a high energy density and cycle life can be achieved, and the shape and size of the battery can be flexibly designed according to requirements.

[0056] According to some embodiments of the present invention, Fig. 9As shown, the battery assembly 1 is constructed as a wound battery. By constructing the battery assembly 1 as a wound battery, the positive electrode sheet 121, the separator 11 and the negative electrode sheet 122 are wound together in sequence and fixed together by welding or bonding, etc., a high power density and charge and discharge rate can be achieved, and it is suitable for batteries of certain shapes, such as cylindrical batteries.

[0057] The vehicle according to the present utility model is briefly described below.

[0058] The vehicle according to the present invention includes the battery assembly 1 in any one of the above embodiments. Since the vehicle according to the present invention includes the battery assembly 1 in any one of the above embodiments, the vehicle according to the present invention has higher reliability, higher endurance and better performance by adopting a high-performance and high-reliability battery assembly 1.

[0059] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0060] In the description of the present invention, "first feature" or "second feature" may include one or more of the features.

[0061] In the description of the present invention, "plurality" means two or more.

[0062] In the description of the present invention, a first feature being “above” or “below” a second feature may include that the first and second features are directly in contact with each other, or may include that the first and second features are not in direct contact but are in contact with each other via another feature therebetween.

[0063] In the description of the present invention, a first feature “above”, “over” and “above” a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0064] In the description of this specification, the description with reference to the terms "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 utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

Claims

1. A battery assembly, characterized in that: The battery assembly comprises: Diaphragm (11); A pole piece (12), the pole piece (12) being arranged on one side of the diaphragm (11) in a thickness direction, the pole piece (12) being provided with a thinned area (12a) so that a gap is formed between the pole piece (12) and the diaphragm (11); A filling piece (13), at least a portion of which is filled into the gap.

2. The battery assembly according to claim 1, characterized in that: The edge of the pole piece in the length direction is provided with a thinned area (12a).

3. The battery assembly according to claim 2, characterized in that: The filling member (13) comprises: A first filling portion (131), the first filling portion (131) being arranged in the gap; A second filling portion (132), the second filling portion (132) is located on a side of the first filling portion (131) away from the pole piece (12).

4. The battery assembly according to claim 3, characterized in that: The thickness of the gap gradually increases in the length direction away from the pole piece (12); and the thickness of the first filling portion (131) gradually increases in the length direction away from the pole piece (12).

5. The battery assembly according to claim 3, characterized in that: The filling member (13) further comprises: An adhesive layer is respectively arranged between the first filling part (131) and the diaphragm (11), and between the second filling part (132) and the diaphragm (11).

6. The battery assembly according to claim 3, characterized in that: The length of the first filling portion (131) is n, the length of the gap is L and the following condition is satisfied: 0.6≤n / L≤1.

7. The battery assembly according to claim 5, characterized in that: The maximum thickness of the first filling portion (131) is a1, the thickness of the glue layer is b, the maximum thickness of the pole piece (12) is c, and the following condition is satisfied: 0.6≤(a1+b) / c≤1.

8. The battery assembly according to claim 5, characterized in that: The thickness of the second filling portion (132) is a2, the expansion rate of the second filling portion (132) is e, the thickness of the glue layer is b, the thickness of the pole piece (12) is c and the following conditions are satisfied: 1≤(a2*e+b) / c≤1.

05.

9. The battery assembly according to claim 1, characterized in that: The pole pieces (12) comprise a positive pole piece (121) and a negative pole piece (122); one of the positive pole piece (121) or the negative pole piece (122) is arranged between two adjacent diaphragms (11); the thinned area (12a) of the positive pole piece (121) and the thinned area (12a) of the negative pole piece (122) are located on the same side or on different sides of the battery assembly.

10. A vehicle, characterized in that: A battery assembly (1) comprising any one of claims 1 to 9.

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