Battery case and battery

Abstract

The present invention discloses a battery case and a battery. Among them, the battery case is divided into a bottom case and a cover, and the cover is divided into an outer contact layer, an insulating layer, and an inner contact layer. Among them, the electrode contact part of the outer contact layer passes through the insulating layer and the inner contact layer to be electrically connected to one pole of the battery cell, the other pole of the battery cell is electrically connected to the bottom case, and after the inner contact layer is welded to the bottom case, the encapsulation of the battery cell can be realized. Since the inner contact layer and the outer contact layer are insulated by the insulating layer, the bottom case is also insulated from the outer contact layer, thereby preventing the two electrodes of the battery cell from being electrically connected and short-circuited; since the inner contact layer and the outer contact layer of the cover are pre-insulated, when the cover is encapsulated on the bottom case, only the inner contact layer needs to be welded to the bottom case, and there is no need to set an insulating film anymore. Thus, the encapsulation process of the battery can be simplified and the encapsulation efficiency can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a battery case and a battery. Background Art

[0002] For existing button batteries, the battery case is formed by splicing a positive electrode case, a negative electrode case and an insulating plastic sleeve. Insulation is required between the positive electrode case and the negative electrode case to prevent the button battery from short - circuiting. In related technologies, insulation is achieved by setting an insulating film between the positive electrode case and the negative electrode case. During related production processes, the entire case is sealed by squeezing the insulating plastic sleeve between the positive electrode case and the negative electrode case, and the positive electrode case and the negative electrode case are welded and fixed. In the processing process, since the existing case encapsulation only relies on the extrusion of the positive electrode case and the negative electrode case, the sealing effect is poor, resulting in a large number of button batteries having liquid leakage. The setting of the insulating film is difficult, resulting in a large processing difficulty for button batteries and reducing the processing efficiency. Summary of the Invention

[0003] The main object of the present invention is to propose a battery case for a button battery, aiming to solve the technical problems of how to improve the battery processing efficiency and sealing performance.

[0004] To achieve the above object, the battery case proposed by the present invention includes a cup - shaped bottom case and a cover for sealing the opening of the bottom case;

[0005] The bottom case includes a circular or oval bottom wall and an annular side wall;

[0006] The cover sequentially includes an outer contact layer, an insulating layer and an inner contact layer from outside to inside;

[0007] The maximum outer diameter D1 of the outer contact layer is smaller than the maximum outer diameter D2 of the inner contact layer;

[0008] The outer contact layer includes an electrode contact portion and a conductive adhesive portion;

[0009] The insulating layer includes an insulating adhesive portion and an insulating opening portion;

[0010] The inner contact layer includes a welding portion, a welding adhesive portion and a welding opening portion;

[0011] A welding support portion is provided at the side wall near the opening;

[0012] The electrode contact portion faces the inside of the bottom case through the insulating opening portion and the welding opening portion, and is used for electrically connecting with one of the poles of the battery cell to form electrical conduction between the outer contact layer and the battery cell;

[0013] The conductive adhesive portion is used for seamlessly bonding with the insulating adhesive portion to enhance the strength of the cover and prevent external water from penetrating into the interior of the battery case;

[0014] The welding part is used for welding connection with the welding support part so as to complete the sealing between the cover and the bottom shell;

[0015] The welding and bonding part is used for seamless bonding with the insulating bonding part to strengthen the strength of the cover, reduce the direct contact area between the insulating bonding part and the inside of the battery case, and prevent external water from penetrating into the inside of the battery case;

[0016] Before the cover and the bottom shell are sealed, the insulating bonding part is melted by a material that is resistant to electrolyte corrosion and has a heat shrinkage rate of 6% or less at a temperature greater than or equal to 100 °C, and is seamlessly bonded with the conductive bonding part and the welding and bonding part. And at room temperature after cooling, the bonding strength between the insulating bonding part and the conductive bonding part and the welding and bonding part is greater than or equal to 1.0 N per square millimeter. The thickness d3 of the insulating bonding part is 0.01 mm - 2.5 mm, and the contact area S0 between the insulating bonding part and the inside of the battery case satisfies S0 <= π * D2 * d3 * 1 / 2.

[0017] Optionally, the material of the outer contact layer is stainless steel, and the thickness d4 of the outer contact layer is 0.1 mm - 0.25 mm; and / or, the material of the inner contact layer is stainless steel, and the thickness d5 of the inner contact layer is 0.1 mm - 0.25 mm.

[0018] Optionally, the material of the insulating layer is one or more of PP, PFA, PVDF, PTFE, ETFE, and PVC.

[0019] Optionally, the bonding strength between the insulating bonding part and the conductive bonding part and the welding and bonding part at room temperature after cooling is less than or equal to 5.0 N / mm.

[0020] Optionally, the area S1 of the insulating bonding part and the area S2 of the insulating layer satisfy S1 / S2 >= 0.6; and / or, the area S1 of the insulating bonding part and the area S3 of the outer contact layer satisfy S1 / S3 >= 0.5.

[0021] Optionally, a first bonding enhancement layer is provided on the first surface layer of the conductive bonding part close to the insulating bonding part to strengthen the bonding strength with the insulating bonding part; and / or, a second bonding enhancement layer is provided on the second surface layer of the welding and bonding part close to the insulating bonding part to strengthen the bonding strength with the insulating bonding part.

[0022] Optionally, the side wall is further provided with an extension part, the extension part protrudes from the welding support part and extends outward by a certain height h, and the extension height h satisfies being greater than or equal to the sum of the thickness d3 of the insulating bonding part and the thickness d4 of the outer contact layer.

[0023] Optionally, the battery case further includes a protection member formed by curing at normal temperature a liquid glue in a groove formed at the outer edge portions of the extension portion, the welding portion, the insulating bonding portion, and the outer contact layer after the cover and the bottom case are sealed.

[0024] Optionally, an insulating unit is provided inside the welding opening portion, and the insulating unit is used to prevent one pole of the battery cell from contacting the inner contact layer to form a short circuit when electrically connected to the electrode contact portion.

[0025] The present invention also provides a battery, including a battery cell and the battery case as described above. One pole of the battery cell is electrically connected to the outer contact layer of the battery case, and the other pole is electrically connected to the inner contact layer and / or the bottom case of the battery case.

[0026] In the present invention, the battery case is divided into a bottom case and a cover, and the cover is divided into an outer contact layer, an insulating layer, and an inner contact layer. Among them, the electrode contact portion of the outer contact layer passes through the insulating layer and the inner contact layer to be electrically connected to one pole of the battery cell, and the other pole of the battery cell is electrically connected to the bottom case. After the inner contact layer and the bottom case are welded, the battery cell can be encapsulated. Since the inner contact layer and the outer contact layer are insulated by the insulating layer, the bottom case is also insulated from the outer contact layer, thereby preventing the two electrodes of the battery cell from conducting short circuits with each other; since the inner contact layer and the outer contact layer of the cover are pre-insulated, when the cover is encapsulated with the bottom case, only the inner contact layer and the bottom case need to be welded, and there is no need to provide an insulating film anymore, thus simplifying the battery encapsulation process and improving the encapsulation efficiency; in addition, by defining the contact area S0 between the insulating bonding portion and the inside of the battery case as S0 <= π * D2 * d3 * 1 / 2, the area of the insulating bonding portion exposed to the electrolyte can be reduced, thereby reducing the corrosion of the insulating layer by the electrolyte to ensure the bonding stability of the insulating layer to the outer contact layer and the inner contact layer. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0028] Figure 1 It is an exploded view of the structure of an embodiment of the battery case of the present invention;

[0029] Figure 2 It is an exploded sectional view of an embodiment of the battery case of the present invention;

[0030] Figure 3 It is a sectional schematic view of an embodiment of the battery case of the present invention;

[0031] Figure 4 It is a schematic cross-sectional view of an embodiment of the cover in the present invention;

[0032] Figure 5 It is an exploded view of the structure of another embodiment of the battery case of the present invention.

[0033] Explanation of the reference numerals in the drawings:

[0034] Label Name Label Name Label Name 10 Bottom case 20 Cover 11 Bottom wall 12 Side wall 21 Outer contact layer 22 Insulating layer 23 Inner contact layer 211 Electrode contact part 212 Conductive bonding part 221 Insulating bonding part 222 Insulating opening part 231 Welding part 232 Welding bonding part 233 Welding opening part 121 Welding support part 213 First bonding reinforcement layer 234 Second bonding reinforcement layer 122 Extension part 30 Protection part 40 Insulating unit 50 Electric core 223 First bonding layer 224 Anti-conduction layer 225 Second bonding layer

[0035] The realization of the object of the present invention, functional features and advantages will be further described with reference to the embodiments and the accompanying drawings. Specific embodiments

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0038] In addition, if there are descriptions such as "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and / or" appearing throughout the text is that it includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, or solution B, or a solution that satisfies both A and B. In addition, the technical solutions between the embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0039] The present invention provides a battery case for a button battery.

[0040] In the embodiments of the present invention, as Figures 1 to 5As shown in the figure, the battery case includes a cup-shaped bottom case 10 and a cover 20 for sealing the opening of the bottom case 10; the bottom case 10 includes a circular or oval bottom wall 11 and an annular side wall 12; the cover 20 sequentially includes an outer contact layer 21, an insulating layer 22 and an inner contact layer 23 from outside to inside; the maximum outer diameter D1 of the outer contact layer 21 is smaller than the maximum outer diameter D2 of the inner contact layer 23; the outer contact layer 21 includes an electrode contact portion 211 and a conductive adhesive portion 212; the insulating layer 22 includes an insulating adhesive portion 221 and an insulating opening portion 222; the inner contact layer 23 includes a welding portion 231, a welding adhesive portion 232 and a welding opening portion 233; a welding support portion 121 is provided near the opening of the side wall 12; the electrode contact portion 211 faces into the bottom case 10 through the insulating opening portion 222 and the welding opening portion 233, and is used for electrically connecting with one pole of the battery cell 50 to form electrical conduction between the outer contact layer 21 and the battery cell 50; the conductive adhesive portion 212 is used for seamlessly bonding with the insulating adhesive portion 221 to enhance the strength of the cover 20 and prevent external water from penetrating into the interior of the battery case; the welding portion 231 is used for welding connection with the welding support portion 121 to complete the sealing of the cover 20 and the bottom case 10; the welding adhesive portion 232 is used for seamlessly bonding with the insulating adhesive portion 221 to enhance the strength of the cover 20, reduce the direct contact area between the insulating adhesive portion 221 and the interior of the battery case, and prevent external water from penetrating into the interior of the battery case;

[0041] Before the cover 20 is sealed with the bottom case 10, the insulating adhesive portion 221 is melted from a material that is resistant to electrolyte corrosion and has a heat shrinkage rate of 6% or less at a temperature greater than or equal to 100 °C, and is seamlessly bonded with the conductive adhesive portion 212 and the welding adhesive portion 232. And at room temperature after cooling, the bonding strength between the insulating adhesive portion 221 and the conductive adhesive portion 212 and the welding adhesive portion 232 is greater than or equal to 1.0 N per square millimeter. The thickness d3 of the insulating adhesive portion 221 is 0.01 mm - 2.5 mm. The contact area S0 between the insulating adhesive portion 221 and the interior of the battery case satisfies S0 <= π * D2 * d3 * 1 / 2. Specifically, for example, d3 can be 0.01 mm, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.5 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.5 mm for specific designs. For small button batteries, it is preferably selected that the thickness d1 is 0.15 mm - 0.25 mm. It should be understood that the specific thickness of the insulating adhesive portion can be specifically designed according to specific products. Preferably, the insulating adhesive portion and the insulating layer 22 are integrally formed structures.

[0042] Compared with the prior art, the battery case of the present application, as compared with the traditional one, uses welding for sealing, which greatly improves the sealing performance and stability, rather than relying on physical force extrusion between the cases for sealing. And since the cover 20 is pre-made, insulation can be achieved through the insulating bonding part 221, which can improve the insulation performance and, under certain conditions, can play a protective role. Further, the cover 20 of the battery case of the present application adopts a three-layer structure, enhancing the stability and reliability of the structure. Since the insulating bonding part is between two layers of stainless steel, it has strong waterproof and anti-electrolyte corrosion properties. The contact area of the insulating bonding part with the outside of the battery case is very small, which can effectively prevent external moisture from entering the battery case. At the same time, when the contact area is small, the path length between the outside of the battery case and the inside of the battery case of the insulating bonding part 221 is relatively long, further avoiding the influence of external moisture, etc. on the internal battery core and electrolyte of the battery case; similarly, for the inside of the battery case, only the inner edge of the insulating bonding part 221 can be in contact with the electrolyte inside the battery case, which can effectively reduce the contact area between the electrolyte and the insulating bonding part 221, effectively protecting the insulating bonding part 221 from the influence of softening and corrosion by the electrolyte, effectively improving the service life of the battery. Further, the path of the insulating bonding part 221 from the inside of the battery case to the outside of the battery case is also relatively long, which can further improve the service life of the battery.

[0043] The bottom case 10 can be made of a stainless steel plate. The opening of the bottom case 10 faces upward to accommodate the battery core 50 and the electrolyte; among them, the bottom wall 11 and the side wall 12 can be integrally injection-molded or welded and fixed, which is not limited here. The outer contact layer 21 and the inner contact layer 23 of the cover 20 can be made of a stainless steel plate. Among them, the outer contact layer 21 is used to connect to one of the electrodes of the battery core 50, and the inner contact layer 23 is connected to the bottom case 10 to connect to the other electrode of the battery core 50. Since there is an insulating layer 22 between the outer contact layer 21 and the inner contact layer 23, the outer contact layer 21 and the inner contact layer 23 are insulated from each other, so that the bottom case 10 and the cover 20 can be insulated from each other to prevent the two electrodes of the battery core 50 from being electrically connected to each other. Thus, both the cover 20 and the bottom wall 11 of the bottom case 10 can form the two output electrodes of the battery, and the short circuit caused by the two output electrodes being electrically connected to each other can be avoided. Compared with the prior art, currently, the case of the button battery uses the upper and lower cases in cooperation, with a plastic insulating ring in the middle. For the side wall of the battery case, it has a three-layer structure, while the side wall 12 of the battery case of the present application can be only one layer. In the case of the same-sized case, the battery case of the present application increases the available internal space, which is beneficial to increasing the capacity of the entire battery.

[0044] The welding part 231, i.e., the inner contact layer 23, is the position for welding with the welding support part 121, and the welding part 231 is provided on the peripheral wall of the inner contact layer 23. The maximum outer diameter D1 of the outer contact layer 21 is smaller than the maximum outer diameter D2 of the inner contact layer 23, that is, the welding part 231 protrudes radially from the peripheral wall of the outer contact layer 21, so as to form a spacing between the peripheral wall of the outer contact layer 21 and the welding support part 121, avoiding the outer contact layer 21 from contacting the side wall 12. The welding opening part 233, i.e., the position where the inner contact layer 23 is opened, and the welding bonding part 232 is used for bonding with the insulating layer 22. Among them, the welding of the welding part 231 to the side wall 12 can not only fix the cover 20 and the bottom case 10 to each other, but also realize the electrical conduction between the inner contact layer 23 and the side wall 12. The insulating opening part 222 of the insulating layer 22 corresponds to the welding opening part 233 of the inner contact layer 23, so that the electrode contact part 211 of the outer contact layer 21 can face the inside of the battery case through the insulating opening part 222 and the welding opening part 233; the insulating opening part 222 and the welding opening part 233 can be opened in the middle of the cover 20, so that the electrode contact part 211 can maintain a sufficient spacing from all positions of the side wall 12.

[0045] The electrode of the battery cell 50 can extend through the insulating opening part 222 and the welding opening part 233 to contact the electrode contact part 211, or the electrode contact part 211 can protrude downward to contact the electrode of the battery cell 50. It should be noted that if the electrode of the battery cell 50 extends upward to contact the electrode contact part 211, the battery cell 50 needs to avoid the inner contact layer 23. The top surface and the bottom surface of the insulating bonding part 221 are respectively fixed to the conductive bonding part 212 and the welding bonding part 232 to realize the insulating connection between the outer contact layer 21 and the inner contact layer 23. The inner contact layer 23 is welded and sealed to the side wall 12, and the outer contact layer 21 and the inner contact layer 23 are seamlessly bonded through the insulating layer 22, so as to realize the sealing of the cover 20 to the bottom case 10. Among them, when welding the inner contact layer 23 to the side wall 12, the insulating connection between the inner contact layer 23 and the outer contact layer 21 has been realized in advance, so there is no need to additionally set an insulating film.

[0046] The insulating layer 22 is made of a material with insulating properties and resistance to electrolyte corrosion. Its thermal shrinkage rate at a temperature greater than or equal to 100°C is 6% or less. The thermal shrinkage rate refers to the volume change of a thermoplastic material due to its inherent thermal expansion rate. That is, when the temperature is greater than or equal to 100°C, the volume change of the insulating layer 22 does not exceed 6% of its original volume. This allows the insulating layer 22 to fully melt and be fully connected to the inner contact layer 23 and the outer contact layer 21 to ensure the bonding effect. The bonding strength between the insulating layer 22 and the conductive bonding part 212 and the welding bonding part 232 at room temperature after cooling is greater than or equal to 1.0 N per square millimeter, which can ensure the bonding stability between the insulating layer 22 and the inner contact layer 23 and the outer contact layer 21. Specifically, the bonding strength between the insulating bonding part 221 and the conductive bonding part 212 and the welding bonding part 232 at room temperature after cooling is less than or equal to 5.0 N / mm to prevent excessive internal stress in the cover 20, thereby avoiding damage to the cover 20 due to internal forces during subsequent processing or use. The thickness d3 of the insulating bonding part 221 is set to 0.01 mm - 2.5 mm, enabling the insulating bonding part 221 to stably withstand temperature or external force changes, improving the bonding stability of the insulating bonding part 221, and at the same time reasonably controlling the overall thickness dimension of the cover 20.

[0047] The contact area S0 between the insulating bonding part 221 and the inside of the battery case satisfies S0 <= π * D2 * d3 * 1 / 2. It should be noted that the contact surface between the insulating bonding part 221 and the inside of the battery case is the area where the insulating opening part 222 is exposed to the electrolyte, that is, the wall area of the insulating opening part 222. The wall area S0 of the insulating opening part 222 = π * d3 * the aperture of the insulating opening part 222. That is, the aperture of the insulating opening part 222 should satisfy being less than or equal to D2 * 1 / 2. Thus, on the basis of ensuring that the thickness d3 of the insulating layer 22 is sufficient, the area of the insulating layer 22 exposed to the electrolyte can be effectively controlled to reduce the corrosion of the insulating layer 22 by the electrolyte or the corrosion of the bonding surface between the insulating layer 22 and the inner contact layer 23, improving the structural stability of the insulating layer 22 and the stability of the bonding strength, avoiding the detachment of the insulating layer 22 from the inner contact layer 23, and effectively improving the overall stability of the battery case.

[0048] The battery case of the present invention is divided into a bottom case 10 and a cover 20, and the cover 20 is divided into an outer contact layer 21, an insulating layer 22 and an inner contact layer 23. Among them, the electrode contact portion 211 of the outer contact layer 21 passes through the insulating layer 22 and the inner contact layer 23 to be electrically connected to one pole of the battery cell 50. The other pole of the battery cell 50 is electrically connected to the bottom case 10. After the inner contact layer 23 is welded to the bottom case 10, the encapsulation of the battery cell 50 can be realized. Since the inner contact layer 23 and the outer contact layer 21 are insulated by the insulating layer 22, the bottom case 10 is also insulated from the outer contact layer 21, thereby preventing the two electrodes of the battery cell 50 from being electrically connected and short-circuited; since the inner contact layer 23 and the outer contact layer 21 of the cover 20 are pre-insulated, when the cover 20 is encapsulated on the bottom case 10, only the inner contact layer 23 needs to be welded to the bottom case 10, and there is no need to set an insulating film anymore, thereby simplifying the encapsulation process of the battery and improving the encapsulation efficiency; in addition, the contact area S0 between the insulating bonding portion 221 and the inside of the battery case is limited to S0 <= π * D2 * d3 * 1 / 2, which can reduce the area of the insulating bonding portion 221 exposed to the electrolyte, thereby reducing the corrosion of the electrolyte on the insulating layer 22 and ensuring the bonding stability of the insulating layer 22 to the outer contact layer 21 and the inner contact layer 23.

[0049] Specifically, the material of the outer contact layer 21 is stainless steel, and the thickness d4 of the outer contact layer 21 is 0.1 mm - 0.25 mm; and / or, the material of the inner contact layer 23 is stainless steel, and the thickness d5 of the inner contact layer 23 is 0.1 mm - 0.25 mm. Specifically, for example, d4 and d5 can be 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.5 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.5 mm for specific designs. The stainless steel can be 304 stainless steel, which contains a relatively high nickel and has an austenitic single-phase structure at room temperature, has high corrosion resistance, good cold forming and weldability, and has high plasticity and toughness at low temperature, room temperature and high temperature. Setting the outer contact layer 21 and the inner contact layer 23 as SUS304 can ensure the structural stability of the cover 20 during the processing process and the chemical stability when used as a battery case.

[0050] Setting the thickness d4 of the outer contact layer 21 and the thickness d5 of the inner contact layer 23 to 0.1 mm - 0.25 mm can not only make the outer contact layer 21 and the inner contact layer 23 have sufficient structural strength, but also reasonably control the overall thickness dimension of the cover 20. In practical applications, the material of the insulating layer 22 is one or more of PP (polypropylene), PFA (a copolymer of a small amount of perfluoropropyl perfluorovinyl ether and polytetrafluoroethylene), PVDF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), ETFE (ethylene-tetrafluoroethylene copolymer), PVC (polyvinyl chloride).

[0051] In one embodiment, the area S1 of the insulating adhesive portion 221 and the area S2 of the insulating layer 22 satisfy S1 / S2 >= 0.6; and / or, the area S1 of the insulating adhesive portion 221 and the area S3 of the outer contact layer 21 satisfy S1 / S3 >= 0.5. Thus, the bonding area between the insulating layer 22 and the outer contact layer 21 can be effectively ensured, and the connection stability between the insulating layer 22 and the outer contact layer 21 can be improved; at the same time, the size of the insulating opening portion 222 can be reasonably controlled to effectively control the area of the electrode contact portion 211 and improve the area utilization rate of the outer contact layer 21.

[0052] In one embodiment, as Figure 3 shown, a first bonding enhancement layer 213 is provided on the first surface layer of the conductive bonding portion 212 close to the insulating adhesive portion 221 for strengthening the bonding strength with the insulating adhesive portion 221; and / or, a second bonding enhancement layer 234 is provided on the second surface layer of the welding bonding portion 232 close to the insulating adhesive portion 221 for strengthening the bonding strength with the insulating adhesive portion 221. The specific form of the first bonding enhancement layer 213 is not limited, as long as it can increase the connection area with the insulating adhesive portion 221 to strengthen the bonding strength. For example, the first bonding enhancement layer 213 can be set as a protrusion. The specific form and function of the second bonding enhancement layer 234 can refer to the first bonding enhancement layer 213. It should be noted that the first bonding enhancement layer 213 and the second bonding enhancement layer 234 can be indirectly matched through the insulating layer 22 to further improve the bonding stability of the outer contact layer 21, the insulating layer 22, and the inner contact layer 23.

[0053] Specifically, as Figure 4 shown, the first bonding enhancement layer 213 is formed by sandblasting the first surface layer of the first stainless steel layer close to the insulating adhesive portion 221 to form a uniform first rough surface layer; and / or the second bonding enhancement layer 234 is formed by sandblasting the second surface layer of the second stainless steel layer close to the insulating adhesive portion 221 to form a uniform second rough surface layer. It can be understood that the "uniform" in this embodiment does not refer to absolute uniformity, but a natural uniform rough surface formed after the first surface layer is sandblasted. The first rough surface layer can make the adhesion force of each part of the first surface layer with the insulating adhesive portion 221 more uniform, thereby avoiding stress concentration. Similarly, the second rough surface layer can also make the adhesion force of each part of the second surface layer with the insulating adhesive portion 221 more uniform. By sandblasting to form the first bonding enhancement layer 213 and the second bonding enhancement layer 234, the processing methods of the first bonding enhancement layer 213 and the second bonding enhancement layer 234 can be simplified to improve the processing efficiency.

[0054] In another embodiment, the first bonding enhancement layer 213 is a first inclined sheet protruding from the first surface layer and having a certain inclination angle with the first surface layer. The height of the first inclined sheet is less than the thickness of the insulating bonding portion 221. The second bonding enhancement layer 234 is a second inclined sheet protruding from the second surface layer and having a certain inclination angle with the second surface layer. The height of the second inclined sheet is less than the thickness of the insulating bonding portion 221. The first inclined sheet and the second inclined sheet have opposite inclination directions and are alternately arranged with each other. The number of the first inclined sheets is multiple and they are distributed on the first surface layer. The melted bonding insulating layer 22 can be filled in the space between two adjacent first inclined sheets to adhesively connect with the side surfaces of the first inclined sheets. The height of the first inclined sheet is the vertical distance between the end of the first inclined sheet and the first surface layer. The height of the first inclined sheet is less than the thickness of the insulating bonding portion 221, which can prevent the first inclined sheet from contacting the second stainless steel layer after passing through the insulating bonding portion 221. The distribution manner and function of the second inclined sheet can refer to those of the first inclined sheet. The first inclined sheet and the second inclined sheet are alternately arranged with each other in the length direction, so that the first inclined sheet and the second inclined sheet can be adjacent to each other after being inserted into the insulating bonding portion 221, thereby enabling the outer contact layer 21 and the inner contact layer 23 to be closer without reducing the thickness of the insulating bonding portion 221, so as to improve the structural strength of the cover 20.

[0055] In yet another embodiment, the first bonding enhancement layer 213 is a first groove recessed from the first surface layer, and the recessed direction of the first groove is away from the insulating bonding layer direction; and / or the second bonding enhancement layer 234 is a second groove recessed from the second surface layer, and the recessed direction of the second groove is away from the insulating bonding layer direction. The number of the first grooves is multiple, and the multiple first grooves are distributed on the first surface layer. The melted insulating bonding portion 221 can be filled in the first grooves to increase the connection area with the first surface layer, thereby enhancing the bonding strength between the outer contact layer 21 and the insulating bonding portion 221. The arrangement manner and function of the second grooves can refer to those of the first grooves and will not be elaborated herein.

[0056] In one embodiment, as Figures 1 to 3 shown, the side wall 12 is further provided with an extension portion 122. The extension portion 122 protrudes from the welding support portion 121 and extends outward by a certain height h. The extension height h satisfies h≥d3 + d4, where d3 is the thickness of the insulating bonding portion 221 and d4 is the thickness of the outer contact layer 21. The extension portion 122 extends upward from the top of the welding support portion 121, and the top of the extension portion 122 protrudes from the top surface of the outer contact layer 21, so that the extension portion 122 can be connected to the protective cover covering the outer contact layer 21, thereby effectively protecting the cover 20.

[0057] Specifically, as Figures 1 to 3As shown, the battery case further includes a protection member 30, which is formed by curing at normal temperature a liquid glue in a groove formed at the outer edge portions of the extension portion 122, the welding portion 231, the insulating bonding portion 221, and the outer contact layer 21 after the cover 20 and the bottom case 10 are sealed. The top surface of the portion where the insulating bonding portion 221 protrudes from the peripheral wall of the outer contact layer 21 forms the bottom of the groove, and the peripheral wall of the outer contact layer 21 and the inner peripheral wall of the extension portion 122 form the walls of the groove, so that the groove extends along the circumferential direction of the outer contact layer 21. The protection member 30 can not only cover the top surface of the protruding portion of the insulating bonding layer, but also effectively isolate the outer contact layer 21 from the extension portion 122, thereby preventing the outer contact layer 21 from forming electrical conduction with the inner contact layer 23 or the side wall 12. It can be understood that setting the protection member 30 to be formed by curing a liquid glue can not only achieve the insulation between the outer contact layer 21 and the inner contact layer 23 or the extension portion 122, but also reduce the acting pressure of the protection member 30 on the outer contact layer 21 or the extension portion 122 to facilitate the deformation of the outer contact layer 21 or the extension portion 122, thereby ensuring the structural stability of the battery case.

[0058] In practical applications, as Figures 1 to 3 shown, an insulating unit 40 is provided inside the welding opening portion 233, and the insulating unit 40 is used to prevent one pole of the battery cell 50 from contacting the inner contact layer 23 to form a short circuit when electrically connected to the electrode contact portion 211. The insulating unit 40 can be arranged in a ring shape and extend along the circumferential direction of the welding opening portion 233. The insulating unit 40 can be close to the hole wall of the welding opening portion 233 to cover the welding opening portion 233, so as to prevent the electrode connected to the electrode contact portion 211 from contacting the inner contact layer 23, and further avoid the short circuit of the two electrodes of the battery cell 50.

[0059] In an embodiment, as Figure 5 shown, the insulating layer 22 may include a laminated first bonding layer 223, a conduction prevention layer 224, and a second bonding layer 225. Among them, the first bonding layer 223 bonds the outer contact layer 21 to the conduction prevention layer 224, and the second bonding layer 225 bonds the inner contact layer 23 to the conduction prevention layer 224, and the conduction prevention layer 224 can ensure the mutual insulation between the outer contact layer 21 and the inner contact layer 23. In this way, the first bonding layer 223 and the second bonding layer 225 only need to have bonding properties, and the conduction prevention layer 224 only needs to have insulation properties. By realizing the two properties of the insulating layer 22 through different functional levels, the bonding properties and insulation properties of the corresponding levels can be strengthened, so as to improve the overall performance of the insulating layer 22.

[0060] The present invention further provides a battery, which includes a battery cell 50 and a battery case. The specific structure of the battery case refers to the above embodiments. Since this battery adopts all the technical solutions of the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one. Among them, one pole of the battery cell 50 is electrically connected to the outer contact layer 21 of the battery case, and the other pole is electrically connected to the inner contact layer 23 and / or the bottom case 10 of the battery case. This battery can be set as a button battery, which is mainly applied to electronic products to provide electrical energy for them. Among them, the electronic products can be earphones, watches, etc., which are electronic products with relatively low operating voltages.

[0061] The above are only optional embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention under the inventive concept of the present invention, or any direct / indirect application in other related technical fields is included in the patent protection scope of the present invention.

Claims

1. A battery case for a button battery, characterized in that, the battery case includes a cup-shaped bottom case and a cover for sealing the opening of the bottom case; the bottom case includes a circular or oval bottom wall and an annular side wall; the cover sequentially includes an outer contact layer, an insulating layer and an inner contact layer from outside to inside; the maximum outer diameter D1 of the outer contact layer is smaller than the maximum outer diameter D2 of the inner contact layer; the outer contact layer includes an electrode contact part and a conductive adhesive part; the insulating layer includes an insulating adhesive part and an insulating opening part; the inner contact layer includes a welding part, a welding adhesive part and a welding opening part; a welding support part is arranged near the opening of the side wall; the electrode contact part faces into the bottom case through the insulating opening part and the welding opening part, and is used for electrically connecting with one pole of the battery cell to form electrical conduction between the outer contact layer and the battery cell; the conductive adhesive part is used for seamlessly bonding with the insulating adhesive part to enhance the strength of the cover and prevent external water from penetrating into the interior of the battery case; the welding part is used for welding connection with the welding support part to complete the sealing of the cover and the bottom case; the welding adhesive part is used for seamlessly bonding with the insulating adhesive part to enhance the strength of the cover, reduce the direct contact area between the insulating adhesive part and the interior of the battery case, and prevent external water from penetrating into the interior of the battery case; before the cover and the bottom case are sealed, the insulating adhesive part is melted from a material that is resistant to electrolyte corrosion and has a heat shrinkage rate of 6% or less at a temperature greater than or equal to 100°C and is seamlessly bonded with the conductive adhesive part and the welding adhesive part, and the bonding strength between the insulating adhesive part and the conductive adhesive part and the welding adhesive part at room temperature after cooling is greater than or equal to 1.0 N per square millimeter. The thickness d3 of the insulating adhesive part is 0.01 mm - 2.5 mm, and the contact area S0 between the insulating adhesive part and the interior of the battery case satisfies S0 <= π * D2 * d3 * 1 / 2; the side wall is further provided with an extension part, the extension part protrudes from the welding support part and extends outward by a certain height h, and the extension height h satisfies being greater than or equal to the sum of the thickness d3 of the insulating adhesive part and the thickness d4 of the outer contact layer; the battery case further includes a protective member, and the protective member is formed by curing a liquid glue at room temperature in a groove formed at the outer edge parts of the extension part, the welding part, the insulating adhesive part and the outer contact layer after the cover and the bottom case are sealed; an insulating unit is arranged inside the welding opening part, and the insulating unit is used to prevent one pole of the battery cell from contacting the inner contact layer to form a short circuit when electrically connecting with the electrode contact part; the insulating unit is arranged in a ring shape and extends along the circumference of the welding opening part, and the insulating unit is close to the hole wall of the welding opening part.

2. The battery case according to claim 1, wherein, The material of the outer contact layer is stainless steel, and the thickness d4 of the outer contact layer is 0.1 mm - 0.25 mm; and / or, the material of the inner contact layer is stainless steel, and the thickness d5 of the inner contact layer is 0.1 mm - 0.25 mm.

3. The battery case according to claim 1, wherein The material of the insulating layer is one or more of PP, PFA, PVDF, PTFE, ETFE and PVC.

4. The battery case according to claim 1, characterized in that, The adhesive strength between the insulating adhesive part and the conductive adhesive part and the welding adhesive part at room temperature after cooling is less than or equal to 5.0 N / mm.

5. The battery case according to claim 1, wherein, The area S1 of the insulating adhesive part and the area S2 of the insulating layer satisfy S1 / S2 >= 0.6; and / or, the area S1 of the insulating adhesive part and the area S3 of the outer contact layer satisfy S1 / S3 >= 0.

5.

6. The battery case according to any one of claims 1 to 5, characterized in that, A first adhesive strengthening layer is provided on the first surface layer of the conductive adhesive part close to the insulating adhesive part for strengthening the adhesive strength with the insulating adhesive part; and / or, a second adhesive strengthening layer is provided on the second surface layer of the welding adhesive part close to the insulating adhesive part for strengthening the adhesive strength with the insulating adhesive part.

7. A battery, characterized in that, It includes an electric core and a battery case as described in any one of claims 1 to 6, one pole of the electric core is electrically connected to the outer contact layer of the battery case, and the other pole is electrically connected to the inner contact layer and / or the bottom case of the battery case.

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