Battery and electric equipment

Abstract

The utility model discloses a battery and electric equipment. The battery comprises a shell, a roll core arranged in the shell and a plurality of elastic pads fixedly arranged in the shell, the side face of the roll core comprises a side plane and two arc side faces connected with the side plane, and side edge protruding edges are formed between the side plane and the arc side faces in a protruding mode. Each elastic pad is provided with a concave face which is opposite to the arc side face. The end part of the roll core is of a non-standard fan-shaped structure, and when the roll core circularly expands, the concave surface of the elastic cushion provides uniform side edge extrusion force for the arc side surface of the roll core, so that the pole piece is prevented from being pulled due to expansion of the battery core, interlayer gaps of the pole piece due to extrusion of the side edge of the roll core are avoided, sudden increase of local stress of the pole piece is avoided, and the pole piece is prevented from being broken due to extrusion; the battery safety is improved; and the interlayer gap of the pole piece is reduced, so that overlarge local current density is avoided, lithium precipitation and polarization phenomena are reduced, the electrochemical property is relatively good, and the service life of the battery is prolonged. Therefore, the safety of the battery can be improved, and the service life of the battery can be prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of energy storage equipment, in particular to a battery and electrical equipment. Background Art

[0002] Lithium-ion batteries, with their advantages of high voltage, high energy density, and no memory effect, are widely used in the automotive industry. As a key component of lithium-ion batteries, the safety and battery life of the battery cell are crucial factors influencing its development. Existing technology, by extruding the curved area on the side of the winding core, improves the space utilization of the winding core within the vehicle casing, allowing for more battery cells and thus extending battery life.

[0003] However, as attached Figure 1 As shown, the cross section of the existing winding core 01 is rectangular, and the convex edges at both ends are chamfered edges, that is, the end of the winding core 01 is formed by a side plane 02 and two arc surfaces 03 that are smoothly connected. After the winding core 01 is squeezed on the arc surface 03, an interlayer gap appears in the inner circle of the pole piece. Due to the lack of limiting constraints on the arc surface 03 of the winding core 01 along the ±45° direction, a pole piece gap 04 appears at the arc surface 03 of the winding core 01. That is, after the side plane 02 of the winding core 01 is squeezed, it will produce a wavy curve deformation, and a pole piece gap 04 will be generated at both ends of the winding core 01. The stress concentration at the pole piece gap 04 is relatively large, as shown in the attached figure. Figure 1 As shown. After research, Figure 2 The stress distribution curve shown is along the ±45° angle of the arc surface 03 of the winding core 01, extending from the inside out. A significant stress increase is observed at the electrode gap 04. This indicates that during cell expansion, the arc surface 03 of the winding core 01 experiences a localized stress surge. Both the tensile force and the concentrated stress increase the risk of electrode fracture, compromising battery safety. Excessively large inter-electrode gaps can lead to excessive local current density during charge and discharge cycles, resulting in lithium deposition and further increased electrode stress. This, combined with polarization, can lead to a low SOH and reduced electrochemical performance, shortening the battery's lifespan.

[0004] Therefore, how to improve the safety and service life of battery cells is a technical problem that needs to be solved by people in this field. Utility Model Content

[0005] The purpose of the utility model is to provide a battery and electrical equipment, in which an elastic pad is added inside the shell to suppress the expansion of the arc side of the winding core, reduce the risk of electrode breakage and electrochemical performance degradation, and solve the technical problems of low safety and service life of existing batteries.

[0006] To achieve the above object, the present utility model provides a battery, comprising a housing, a wound core disposed within the housing, and a plurality of elastic pads fixedly disposed within the housing; the side surface of the wound core includes a side plane and two arc side surfaces respectively connected to the side plane, and a side convex rib is formed by the protrusion between the side plane and the arc side surfaces; each elastic pad has a concave surface opposite to the arc side surface of the wound core.

[0007] Preferably, the wound core is formed by laminating and winding a positive electrode sheet, a negative electrode sheet, and a separator, the elastic pads extend along the length direction of the wound core, the dimension of the elastic pads along the length direction of the wound core is greater than the dimension of the positive electrode sheet along the length direction of the wound core, and both ends of the elastic pads respectively correspond to and extend beyond both ends of the positive electrode sheet.

[0008] Preferably, the difference in the end lengths between the elastic pad and the positive electrode sheet is a set difference, the set difference is L, satisfying: 0mm < L ≤ 8.0mm.

[0009] Preferably, in the natural state, an arc gap is formed between the concave surface and the arc side surface.

[0010] Preferably, the radial spacing of the arc gap is a set spacing, the set spacing is G, satisfying: G = r - R, and 0.1mm < G ≤ 8.0mm; wherein, R is the radius of the arc side surface, r is the radius of the concave surface, and the units are both mm.

[0011] Preferably, the elastic pad includes a transverse side surface extending in a direction perpendicular to the side plane and a vertical side surface extending in a direction parallel to the side plane, and the transverse side surface, the vertical side surface, and the concave surface are connected in sequence.

[0012] Preferably, the transverse side surface and the vertical side surface respectively correspond to and are in contact with adjacent side surfaces of the housing.

[0013] Preferably, in the direction close to the arc side surface, the thickness of the elastic pad gradually decreases.

[0014] Preferably, the width of the transverse side surface is W, satisfying: (R - P) * 0.60 < W < (R - P) * 0.85, wherein, R is the radius of the arc side surface, P is the side compression distance of the arc side surface, and the units are both mm.

[0015] Preferably, the width of the transverse side surface is W, and the width of the vertical side surface is T, satisfying: W * 0.62 < T < W * 0.96.

[0016] Preferably, the width of the vertical side surface is T, and also satisfies: T < W.

[0017] The present utility model also provides an electrical equipment, comprising the above battery.

[0018] Compared with the background technology, the utility model optimizes the internal structure of the battery. On the one hand, the side structure of the core is optimized. The optimized side of the core includes a side plane and two arc side surfaces respectively connected to the side plane. A convex side ridge is formed between the side plane and the arc side surface to replace the original rectangular chamfered corner continuous structure, providing conditions for the setting of the elastic pad; on the other hand, a plurality of elastic pads are fixed in the shell, and the core is arranged in the shell. Each elastic pad has a concave surface, which is opposite to the arc side surface of the core; during the cyclic expansion process of the core, the concave surface of the elastic pad is against the arc side surface of the core. The elastic pad undergoes elastic deformation, and the concave surface of the elastic pad provides uniform side extrusion pressure for the arc side of the winding core, limiting the pulling force on the pole piece due to the expansion of the winding core, effectively providing uniform pressure constraint for the winding core, and avoiding the pole piece from generating interlayer gaps due to the extrusion of the side of the winding core, thereby avoiding the situation of local stress surge in the pole piece, reducing the risk of the pole piece breaking due to extrusion, and improving the safety of the battery; in addition, the situation of interlayer gaps in the pole piece is reduced, avoiding the problem of excessive local current density, reducing lithium plating and polarization phenomena, improving electrochemical performance, and helping to extend the service life of the battery. Therefore, the utility model improves the safety and service life of the battery at the same time by adding an elastic pad in the shell.

[0019] The electrical equipment provided by the utility model, including the above-mentioned battery, has the same beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0021] Figure 1 The gap between the pole pieces generated at both ends of the existing winding core;

[0022] Figure 2 It is the stress distribution curve of the arc surface of the existing winding core.

[0023] Figure 3 A schematic diagram of the structure of a battery provided in an embodiment of the present utility model;

[0024] Figure 4 for Figure 1 Schematic cross-section diagram;

[0025] Figure 5 for Figure 1 Schematic diagram of the layout of the flexible pad and the winding core;

[0026] Figure 6 for Figure 1 Schematic diagram of the cross section of the flexible pad;

[0027] Figure 7 for Figure 1 Schematic diagram of the key dimensions of the flexible pad.

[0028] The reference numerals are as follows:

[0029] Winding core 01, side plane 02, arc surface 03 and pole piece gap 04;

[0030] Shell 1 , winding core 2 , arc side surface 22 , elastic pad 3 , concave surface 31 , lateral side surface 32 , vertical side surface 33 , arc gap 4 , positive electrode column 5 and negative electrode column 6 . DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] In order to enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] The present utility model discloses a battery, as shown in the attached Figure 3 As shown, it includes a shell 1, a core 2 and a plurality of elastic pads 3. The core 2 includes a plurality of windings, and all the windings are stacked along the thickness direction of the shell 1. It should be noted that before being installed in the shell 1, the arc side surface 22 is a smooth arc profile. After the core 2 is installed in the shell 1, the arc side surface 22 is squeezed and deformed, and presses against the side of the shell 1. The side compression distance of the arc side surface 22 is P. At this time, the arc side surface 22 is a non-standard fan-shaped structure, that is, the side structure of the core 2 is changed. The side surface of the changed core 2 includes a side plane 21 and two sections of arc side surfaces 22 respectively connected to the side plane 21. A side ridge 23 is formed between the side plane 21 and the arc side surface 22. The side plane 21 is opposite to the side of the shell 1.

[0034] All elastic pads 3 are fixed in the housing 1. As a preferred embodiment, as shown in the attached Figure 4As shown, all elastic pads 3 are fixed at different inner corners of the outer shell 1. Each elastic pad 3 has a concave surface 31, and the concave surfaces 31 of all elastic pads 3 are respectively opposite to all the arc side surfaces 22 of the core 2. The concave surface 31 is preferably an arc concave surface. It should be noted that in the natural state, that is, the battery cell is not expanded, the concave surface 31 does not contact the arc side surface 22; only when the core 2 is expanded and deformed, the concave surface 31 contacts the arc side surface 22. As a preferred embodiment, after the core 2 is expanded and deformed, the radii of the concave surface 31 and the arc side surface 22 are equal, ensuring that the concave surface 31 uniformly applies extrusion pressure to the arc side surface 22, thereby ensuring that the arc side surface 22 is uniformly stressed. It should also be noted that if the core 2 is composed of a plurality of windings stacked together, the elastic pad 3 only counteracts the windings located at the top and bottom layers. Specifically, the shell 1 is a rectangular shell, and an elastic pad 3 is fixed on each of the four inner corners extending along the length direction of the shell 1. Each elastic pad 3 is parallel to the side of the winding core 2. Each elastic pad 3 can be a silicone pad. However, no matter what material the elastic pad 3 is made of, it is necessary to ensure that the elastic pad 3 itself has a certain elasticity so that the elastic pad 3 can provide extrusion constraints for the arc side 22 of the winding core 2 with the help of elastic force.

[0035] The utility model optimizes the internal structure of the battery. On the one hand, the side structure of the core 2 is optimized. The optimized side of the core 2 includes a side plane 21 and two arc side surfaces 22 respectively connected to the side plane 21. A side ridge 23 is formed between the side plane 21 and the arc side surface 22 to replace the original rectangular chamfered continuous structure, providing conditions for the arrangement of the elastic pad 3. On the other hand, during the cyclic expansion process of the core 2, the concave surface 31 of the elastic pad 3 is against the arc side surface 22 of the core 2, and the concave surface 31 of the elastic pad 3 is the core 2. The arc side surface 22 provides a uniform side extrusion pressure, which limits the pulling force on the electrode due to the expansion of the core 2, effectively provides a uniform pressure constraint for the core 2, and avoids the generation of interlayer gaps in the electrode due to the extrusion of the side of the core 2, thereby avoiding the occurrence of local stress surges in the electrode, reducing the risk of the electrode breaking due to extrusion, and improving the safety of the battery; in addition, the occurrence of interlayer gaps in the electrode is reduced, avoiding the problem of excessive local current density, reducing lithium plating and polarization phenomena, and improving the electrochemical performance, which is conducive to extending the service life of the battery.

[0036] In summary, the present invention improves both the safety and the service life of the battery by adding the elastic pad 3 in the housing.

[0037] As attached Figure 3 As shown, the winding core 2 is formed by stacking and winding the positive electrode sheet, the negative electrode sheet and the separator, and the elastic pad 3 extends along the length direction of the winding core 2, that is, the elastic pad 3 is attached to the core 2. Figure 3In the Y-axis direction, ensure that the concave surface 31 abuts against the arc-shaped side surface 22. The dimension of the elastic pad 3 along the length direction of the core 2 is greater than the dimension of the positive electrode plate along the length direction of the core, and both ends respectively correspond to being set beyond both ends of the positive electrode plate, that is, both ends of the elastic pad 3 extend beyond both ends of the core 2, ensuring that the elastic pad 3 can completely cover the arc-shaped side surface 22 of the core 2, so that the elastic pad 3 forms a complete constraint on the opposite arc-shaped side surface 22, avoiding the situation that both ends of the core 2 exceed the elastic pad 3, and in the process of cyclic expansion of the core 2, the part of the arc-shaped side surface 22 that exceeds the elastic pad 3 still has the problem of extrusion stress concentration, avoiding excessive local stress and the risk of the electrode plate still breaking, and further improving the safety of the battery.

[0038] The difference in the end lengths of the elastic pad 3 and the positive electrode plate is a set difference, and the set difference is L, satisfying: 0mm < L ≤ 8.0mm, specifically it can be 1mm, 1.5mm, 2mm, 5mm or 8mm, as shown in the appendix Figure 3 to ensure that the concave surface 31 of the elastic pad 3 can completely cover the arc-shaped side surface 22 of the core 2 during the cyclic expansion process.

[0039] In the natural state, that is, the state where the core 2 does not undergo cyclic expansion, an arc-shaped gap 4 is formed between the concave surface 31 and the arc-shaped side surface 22 to leave space for the expansion of the arc-shaped side surface 22 of the core 2.

[0040] The radial spacing of the arc-shaped gap 4 is a set spacing, and the set spacing is G, as shown in the appendix Figure 5 to satisfy: G = r - R, and 0.1mm < G ≤ 8.0mm, specifically it can be 1mm, 1.5mm, 2mm, 5mm or 8mm; where R is the radius of the arc-shaped side surface 22, and r is the radius of the concave surface 31, and the units are both mm, ensuring that the distance between the concave surface 31 of the elastic pad 3 and the arc-shaped side surface 22 of the core 2 is appropriate. On the one hand, avoid the spacing of the arc-shaped gap 4 being too large so that the elastic pad 3 cannot play a role in restraining the expansion of the core 2, thereby avoiding insufficient binding force due to insufficient contact pressure between the elastic pad 3 and the arc-shaped side surface 22 of the core 2, effectively reducing the risk of fracture of the electrode plate caused thereby, and improving the safety of the battery; on the other hand, avoid the spacing of the arc-shaped gap 4 being too small and affecting the interference amount when the core 2 is installed in the housing 1, and eliminating the resulting problem of inability to assemble.

[0041] As shown in the appendix Figure 6 As shown, in addition to the concave surface 31, the elastic pad 3 further includes a transverse side surface 32 and a vertical side surface 33. The transverse side surface 32 extends along the direction perpendicular to the side plane 21, that is, along the Figure 6 X-axis direction in the appendix. The vertical side surface 33 extends along the direction parallel to the side plane 21, that is, along the Figure 6extends in the Z-axis direction. The lateral side 32 is opposite to the upper or lower surface of the housing 1, and the vertical side 33 is opposite to the side surface of the housing 1. The lateral side 32 is perpendicular to the vertical side 33, and the lateral side 32, the vertical side 33, and the concave surface 31 are connected in sequence. To make the elastic pad 3 provide uniform binding force, the lateral side 32 and the concave surface 31 and the vertical side 33 and the concave surface 31 are smoothly connected by arc convex surfaces.

[0042] As shown in the appendix Figure 4 As shown, the lateral side 32 and the vertical side 33 of the elastic pad 3 are respectively in corresponding contact with the adjacent side surfaces of the housing 1, ensuring that the contact surface between the elastic pad 3 and the housing 1 is large enough, so that the elastic pad 3 is reliably fixed in the housing 1. As a preferred embodiment, the lateral side 32 of the elastic pad 3 is adhesively fixed to the upper or lower surface of the housing 1, and the vertical side 33 is adhesively fixed to the side surface of the housing 1.

[0043] As shown in the appendix Figure 6 As shown, in the direction close to the arc side surface 22, the thickness of the elastic pad 3 gradually decreases, so that the elastic pad 3 can not only structurally adapt to the space between the inner edge angle of the housing 1 and the arc side surface 22 of the core 2, but also ensure that the concave surface 31 of the elastic pad 3 applies uniform extrusion pressure to the arc side surface 22 of the core 2.

[0044] As shown in the appendix Figure 5 As shown, as a preferred embodiment, the optimal dimensions of the elastic pad 3 are: the width of the lateral side 32 is W, satisfying: (R - P)*0.60 < W < (R - P)*0.85, where R is the radius of the arc side surface 22, P is the side compression distance of the arc side surface 22, and the units are both mm; the width of the vertical side 33 is T, satisfying: W*0.62 < T < W*0.96. By reasonably setting W and T, it is ensured that the elastic pad 3 completely covers the arc side surface 22 of the core 2 and provides uniform extrusion constraint for the arc side surface 22.

[0045] W < B, where B is the minimum compression distance of the concave surface 31 along the width direction of the housing 1, leaving a certain space margin for the arc side surface 22 of the core 2 to be extruded and deformed against the side surface of the housing 1, avoiding stress concentration, and increasing the centripetal force constraint of the elastic pad 3 on the arc side surface 22 of the core 2.

[0046] The width of the vertical side 33 is T, as shown in the appendix Figure 7As shown, it also satisfies: T < W, ensuring that the remaining space after the arc side 22 of the core 2 is extruded is a non-standard sector area, enabling the size of the elastic pad 3 to match this area and achieving uniform extrusion of the arc side 22. By reasonably adjusting the values of W and T, the elastic pad 3 can match different side compression distances, generating a uniform contact force on the arc side 22 of the core 2, which can better constrain and protect the core 2 and prevent the pole piece from breaking due to excessive strain.

[0047] As shown in the appendix Figure 3 As shown, the battery further includes a positive electrode post 5 and a negative electrode post 6 fixedly arranged on the outer shell 1, and the positive electrode post 5 and the negative electrode post 6 are fixedly arranged at one end of the core 2. As a preferred embodiment, the positive electrode post 5 and the negative electrode post 6 are distributed along the width direction of the core 2, and the two are electrically connected to the positive electrode sheet and the negative electrode sheet of the core 2 through pole ears.

[0048] The present utility model also provides an electrical device, including the above battery, which has the same beneficial effects.

[0049] It should be noted that in this specification, relational terms such as first and second are only used to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0050] In this article, specific examples are used to elaborate on the principle and implementation manner of the present utility model. The description of the above embodiments is only used to help understand the method and its core idea of the present utility model. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and modifications can be made to the present utility model, and these improvements and modifications also fall within the protection scope of the claims of the present utility model.

Claims

1. A battery, characterized in that: It includes a housing (1), a winding core (2) disposed within the housing (1), and a plurality of elastic pads (3) fixedly arranged within the housing (1); the side surface of the winding core (2) includes a side plane (21) and two arc side surfaces (22) respectively connected to the side plane (21), and a side rib (23) is formed in a convex shape between the side plane (21) and the arc side surfaces (22); each elastic pad (3) has a concave surface (31), and the concave surface (31) faces the arc side surface (22) of the winding core (2).

2. The battery according to claim 1, characterized in that The winding core (2) is formed by laminating and winding a positive electrode sheet, a negative electrode sheet, and a separator, the elastic pad (3) extends along the length direction of the winding core (2), the dimension of the elastic pad (3) along the length direction of the winding core (2) is greater than the dimension of the positive electrode sheet along the length direction of the winding core (2), and both ends of the elastic pad (3) respectively correspond to be disposed beyond both ends of the positive electrode sheet.

3. The battery according to claim 2, characterized in that The difference in the end lengths between the elastic pad (3) and the positive electrode sheet is a set difference, the set difference is L, and it satisfies: 0mm < L ≤ 8.0mm.

4. The battery according to any one of claims 1 to 3, characterized in that An arc gap (4) is formed between the concave surface (31) and the arc side surface (22).

5. The battery according to claim 4, characterized in that The radial spacing of the arc gap (4) is a set spacing, the set spacing is G, and it satisfies: G = r - R, and 0.1mm < G ≤ 8.0mm; where, R is the radius of the arc side surface (22), r is the radius of the concave surface (31), and the units are both mm.

6. The battery according to any one of claims 1 to 3, characterized in that The elastic pad (3) includes a transverse side surface (32) extending in a direction perpendicular to the side plane (21) and a vertical side surface (33) extending in a direction parallel to the side plane (21), and the transverse side surface (32), the vertical side surface (33), and the concave surface (31) are connected in sequence.

7. The battery according to claim 6, characterized in that The transverse side surface (32) and the vertical side surface (33) respectively correspond to be in close contact with adjacent side surfaces of the housing (1).

8. The battery according to claim 6, characterized in that In the direction close to the arc side surface (22), the thickness of the elastic pad (3) gradually decreases.

9. The battery according to claim 6, characterized in that The width of the transverse side surface (32) is W, and it satisfies: (R - P) * 0.60 < W < (R - P) * 0.85, where, R is the radius of the arc side surface (22), P is the side compression distance of the arc side surface (22), and the units are both mm.

10. The battery according to claim 9, characterized in that The width of the transverse side surface (32) is W, and the width of the vertical side surface (33) is T, and it satisfies: W * 0.62 < T < W * 0.

96.

11. The battery according to claim 10, characterized in that The width of the vertical side surface (33) is T, and it also satisfies: T < W.

12. An electrical device, characterized in that: It includes the battery according to any one of claims 1 to 11.

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