Battery and manufacturing method

Abstract

The invention relates to the technical field of energy storage equipment, in particular to a battery and a manufacturing method, and the battery comprises a roll core, a shell, a flow guide needle and an elastic ball. The shell is provided with an opening, a containing space, a necking-down space and a containing space which are sequentially communicated, the elastic ball and the shell are extruded, the shell forms the containing space, and the elastic ball is located in the containing space and blocks the opening. The roll core is located in the containing space, the first pole piece is arranged on the outermost side of the roll core and abuts against the inner wall of the shell, and the shell can serve as first pole output. One end of the flow guide needle is inserted into the roll core and is connected to the second pole piece of the roll core, and the other end of the flow guide needle penetrates through the elastic ball and is positioned outside the shell. The manufacturing method is used for manufacturing the battery and comprises a sealing process: processing the necking structure on the shell, sleeving the elastic ball on the flow guide needle, pushing the elastic ball into the shell, extruding the shell and sealing and forming the elastic ball.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage devices, and particularly to a battery and a manufacturing method thereof. Background Art

[0002] The size of a micro-cylindrical battery is small, and the diameter of the battery is generally in the range of 4 mm - 8 mm. In the battery necking process, the conventional technology uses a hob to cut into the shell to process the necking, and the cutting depth is generally in the range of 15% - 25% of the depth. However, due to the too small size of the micro-cylindrical battery, a precision hob needs to be used to cut into the shell, and the accuracy requirements for parameters such as the feed speed and feed distance are both ±0.02 mm. The processing difficulty is high, the accuracy is difficult to guarantee, and the product qualification rate is relatively low. Moreover, the welding of the positive and negative electrode tabs of the micro-cylindrical battery is also very difficult, which will also affect the product qualification rate and production efficiency. Summary of the Invention

[0003] An object of the present invention is to provide a battery that can improve the product qualification rate and production efficiency.

[0004] To achieve this purpose, the present invention adopts the following technical solutions:

[0005] Provide a battery, including a winding core, a shell, a current collector pin, and an elastic ball. The shell has an opening, a receiving space, a necking space, and a containing space that are sequentially communicated. After the elastic ball and the shell are extruded, the shell forms the receiving space. The elastic ball is located at the receiving space and blocks the opening. The winding core is located in the containing space. The outermost side of the winding core is the first-pole electrode tab, and the first-pole electrode tab abuts against the inner wall of the shell. One end of the current collector pin is inserted into the winding core and connected to the second-pole electrode tab of the winding core, and the other end of the current collector pin passes through the elastic ball and is located outside the shell.

[0006] Optionally, the ratio E of the volume of the elastic ball before extrusion to the volume after extrusion satisfies 30% ≤ E ≤ 60%.

[0007] Optionally, the radius of the opening of the shell after extrusion is d, and the radius of the largest cross-section perpendicular to the axial direction of the shell of the receiving space is D, satisfying 20% ≤ d / D ≤ 40%.

[0008] Optionally, along the axial direction of the shell, the perpendicular distance from the end of the shell where the opening is provided before extrusion to the end of the necking space close to the opening is A, and the overall height of the battery is B, satisfying 10% ≤ A / B ≤ 15%.

[0009] Optionally, along the radial direction of the housing, the necking depth of the necking space is a, and the radius of the maximum cross-section of the accommodating space perpendicular to the axial direction of the housing is b, satisfying 12% ≤ a / b ≤ 15%.

[0010] Optionally, the guide needle extends along the axial direction of the housing.

[0011] Optionally, the guide needle is welded to the second pole piece.

[0012] Optionally, the first pole piece is a positive pole piece, and the second pole piece is a negative pole piece.

[0013] Another object of the present invention is to provide a manufacturing method capable of improving the qualified rate and production efficiency of the battery.

[0014] To achieve this object, the present invention adopts the following technical solutions:

[0015] Provide a manufacturing method for manufacturing the above battery, and the manufacturing method includes the following steps:

[0016] Sealing process: Process a necking structure on the housing, sleeved the elastic ball on the guide needle, and push it into the housing, and extrude the housing and the elastic ball to form a seal.

[0017] Optionally, before the sealing process, the following steps are further included:

[0018] Inserting into the housing: Weld the guide needle to the second pole piece, wind the first pole piece, the separator and the second pole piece with the guide needle to form the core, and after the core is infiltrated with the electrolyte, load it into the housing.

[0019] The beneficial effects of the present invention:

[0020] The present invention provides a battery, which includes a core, a housing, a guide needle and an elastic ball. Among them, the housing has an opening, a containing space, a necking space and an accommodating space that are sequentially communicated. The elastic ball and the housing are extruded, and the housing forms a containing space. The elastic ball is located at the containing space and seals the opening. There is a pressing force between the elastic ball in the compressed state and the inner wall of the containing space, which can ensure the sealing effect. The necking part no longer needs to ensure the sealing effect, and the processing accuracy of the necking part can be greatly reduced, thereby improving the qualified rate of the product. The core is located in the accommodating space, the outermost side of the core is the first pole piece, and the first pole piece abuts against the inner wall of the housing, and the housing can serve as the first pole output. One end of the guide needle is inserted into the core and connected to the second pole piece of the core, and the other end of the guide needle passes through the elastic ball and is located outside the housing, and the guide needle can serve as the second pole output. Therefore, the battery no longer needs to weld the positive and negative electrodes, which can improve the production efficiency.

[0021] The present invention also provides a manufacturing method for manufacturing the above battery. The manufacturing method includes a sealing process: a necking structure is processed on the housing, an elastic ball is sleeved on the diversion needle and pushed into the housing, and the housing and the elastic ball are squeezed to form a seal. The battery obtained by applying the above manufacturing method has a higher qualification rate and production efficiency. Description of the Drawings

[0022] Figure 1 FIG. 6 is a schematic structural diagram of the battery (excluding the winding core) provided by an embodiment of the present invention from a first perspective;

[0023] Figure 2 FIG. 10 is a partially exploded schematic diagram of the battery provided by an embodiment of the present invention;

[0024] Figure 3 FIG. 14 is a cross-sectional view of the battery provided by an embodiment of the present invention;

[0025] Figure 4 FIG. 18 is a schematic structural diagram of the battery provided by an embodiment of the present invention from a second perspective;

[0026] Figure 5 FIG. 22 is a schematic structural diagram of the housing before the necking process provided by an embodiment of the present invention;

[0027] Figure 6 FIG. 26 is a schematic structural diagram of the housing after the necking process provided by an embodiment of the present invention;

[0028] Figure 7 FIG. 30 is a schematic structural diagram of the housing after the process of inserting into the housing provided by an embodiment of the present invention.

[0029] In the figures:

[0030] 1. Winding core; 2. Housing; 21. Opening; 22. Accommodating space; 23. Necking space; 24. Receiving space;

[0031] 3. Diversion needle; 4. Elastic ball. Detailed Embodiments

[0032] The technical solutions of the present invention will be further described below in conjunction with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. In addition, it should be noted that only the parts related to the present invention are shown in the drawings for the convenience of description, rather than all of them.

[0033] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0034] In the present invention, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over", and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath", and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0035] The battery has a small size, and the diameter of the battery is generally in the range of 4 mm to 8 mm. In the battery necking process, the conventional technology uses a hob to cut into the shell for processing the necking, and the cutting depth is generally in the range of 15% - 25% of the depth. However, due to the too small size of the battery, a precision hob needs to be used to cut into the shell, and the accuracy requirements for parameters such as the feed speed and feed distance are both ±0.02 mm. The processing difficulty is high, and it is very difficult to guarantee the accuracy, resulting in a low product qualification rate. Moreover, the difficulty of welding the positive and negative electrode tabs of the battery is also very high, which will also affect the product qualification rate and production efficiency.

[0036] Therefore, the present embodiment provides a battery to solve the above problems, and this battery can improve the product qualification rate and production efficiency.

[0037] Such as Figures 1-4As shown in the figure, the battery of this embodiment includes a wound core 1, a housing 2, a current collector pin 3, and an elastic ball 4. Among them, the housing 2 has an opening 21, a receiving space 22, a necking space 23, and a containing space 24 that are sequentially connected. After the elastic ball 4 and the housing 2 are extruded, the housing 2 forms the receiving space 22, and the elastic ball 4 is located at the receiving space 22 and seals the opening 21. There is a pressing force between the elastic ball 4 in the compressed state and the inner wall of the receiving space 22, which can ensure the sealing effect. The necking part no longer needs to ensure the sealing effect, and the processing accuracy of the necking part can be greatly reduced, thereby improving the qualified rate of the product. The wound core 1 is located in the containing space 24. The outermost side of the wound core 1 is the first pole tab, and the first pole tab abuts against the inner wall of the housing 2, and the housing 2 can act as the first pole output. One end of the current collector pin 3 is inserted into the wound core 1 and connected to the second pole tab of the wound core 1, and the other end of the current collector pin 3 passes through the elastic ball 4 and is located outside the housing 2, and the current collector pin 3 can act as the second pole output. Therefore, the battery no longer needs to weld the positive and negative electrodes, which can improve the production efficiency.

[0038] Optionally, in this embodiment, the material of the elastic ball 4 is rubber, and the rubber material has appropriate elasticity, structural strength, and insulation.

[0039] Optionally, the ratio E of the volume of the elastic ball 4 before extrusion to the volume after extrusion satisfies 30% ≤ E ≤ 60%. This ratio E can be called the compression ratio. When the compression ratio E is less than 30%, the deformation of the elastic ball 4 is insufficient, the sealing pressure is too small, and there is an easy problem with the sealing performance, resulting in a risk of liquid leakage. When the compression ratio E is greater than 60%, the deformation of the elastic ball 4 is too large, and there is a risk of rupture of the elastic ball 4. When the rupture is large, it will cause serious liquid leakage or short-circuit problems. Therefore, 30% - 60% is the most suitable value range for the compression ratio E, which can avoid the above problems.

[0040] As Figure 4 shown, optionally, the radius of the opening 21 of the housing 2 after extrusion is d, that is, the opening 21 of the housing 2 will shrink after extrusion, but it is still circular, and the radius of the shrunk opening 21 is d. The radius of the largest cross-section perpendicular to the axial direction of the housing 2 of the receiving space 22 is D, that is, when the receiving space 22 projects onto a plane perpendicular to the axial direction of the housing 2, the radius of the projected circle is D, and 20% ≤ d / D ≤ 40% is satisfied. When d / D is less than 20%, the opening 21 of the housing 2 is too close to the current collector pin 3, and the positive and negative electrodes of the battery are likely to be short-circuited, causing the battery to short-circuit. When d / D is greater than 40%, the wrapping area of the housing 2 for the elastic ball 4 is insufficient, the compression ratio of the elastic ball 4 cannot reach the process standard, and the battery will have a risk of liquid leakage. Satisfying 20% ≤ d / D ≤ 40% can avoid the above problems, prevent short-circuit and liquid leakage, and improve the qualified rate of the battery.

[0041] As Figure 6As shown, optionally, along the axial direction of the housing 2, the vertical distance from the end of the non-extruded housing 2 where the opening 21 is formed to the end of the necking space 23 close to the opening 21 is A, and the overall height of the battery is B, satisfying 10% ≤ A / B ≤ 15%. The end of the non-extruded housing 2 where the opening 21 is formed to the end of the necking space 23 close to the opening 21 is used to squeeze and form the accommodating space 22, so its size ratio is related to the size of the accommodating space 22. When A / B is less than 10%, the accommodating space 22 is insufficient. When the size of the elastic ball 4 remains unchanged, the area of the housing 2 for squeezing the elastic ball 4 is insufficient, which will cause the opening 21 of the housing 2 after extrusion to be too large, the wrapping area of the housing 2 for the elastic ball 4 to be insufficient, and the compression ratio of the elastic ball 4 not to reach the process standard, resulting in a risk of battery leakage. When A / B is greater than 15%, the proportion of the material of the housing 2 for enclosing the accommodating space 24 is insufficient, which will cause the volume energy density of the battery to decrease. Therefore, in order to balance the above problems, in this embodiment, the value range of A / B is 10% - 15%.

[0042] As Figure 6 shown, optionally, along the radial direction of the housing 2, the necking depth of the necking space 23 is a, and the radius of the maximum cross-section of the accommodating space 24 perpendicular to the axial direction of the housing 2 is b, 12% ≤ a / b ≤ 15%. When a / b is less than 12%, the necking depth is insufficient, and the supporting surface at one end of the elastic ball 4 is too small, resulting in insufficient supporting force and prone to problems such as liquid leakage due to poor sealing. On the premise of reducing the accuracy of the necking process to improve production efficiency, when a / b is greater than 15%, the probability of necking breakage problems occurring in the necking process is relatively high. In order to avoid the above problems and ensure product quality, in this embodiment, the value range of a / b is 12% - 15%.

[0043] Optionally, the current collector pin 3 extends along the axial direction of the housing 2 to prevent the current collector pin 3 from approaching the edge of one side of the opening 21 of the housing 2. Optionally, the current collector pin 3 is welded to the second pole piece, and welding can ensure the connection strength between the two to avoid disconnection and causing quality problems.

[0044] Optionally, the first pole piece is the positive pole piece, and the second pole piece is the negative pole piece. That is, in this embodiment, the housing 2 is the positive output terminal, and the current collector pin 3 is the negative output terminal.

[0045] Table 1

[0046]

[0047] To verify that the battery provided in this embodiment has a higher overall yield, Table 1 above provides a group of examples and six groups of comparative examples of batteries. Among them, the size ratio of the battery in Example 1 conforms to all of the above more optimal size ranges. The appearance of this group of batteries is good, the sealing position is smooth and flat, the flow guide pin 3 coincides with the axis of the housing 2, the airtightness detection meets the requirements, and the overall yield is higher than 99%. It can be seen that conforming to all of the above more optimal size ranges can improve the product qualification rate of the battery.

[0048] For the battery in Comparative Example 1, the ratio of the vertical distance A from the end of the non-extruded housing 2 where the opening 21 is opened to the end of the necking space 23 close to the opening 21 to the overall height B of the battery is 8%, which is less than the minimum value of 10% of the above more optimal range. And the ratio of the radius d of the opening 21 of the extruded housing 2 of this group of batteries to the radius D of the maximum cross-section perpendicular to the axis of the housing 2 of the accommodating space 22 is 66%, which is greater than the maximum value of 40% of the above more optimal range. For this group of batteries, the elastic ball 4 is exposed more, the sealing position is smooth and flat, the flow guide pin 3 coincides with the axis of the housing 2, but the airtightness detection is unstable, there is a certain risk of liquid leakage, and the overall yield is only greater than 92%.

[0049] For the battery in Comparative Example 2, the ratio of the vertical distance A from the end of the non-extruded housing 2 where the opening 21 is opened to the end of the necking space 23 close to the opening 21 to the overall height B of the battery is 17%, which is greater than the maximum value of 15% of the above more optimal range. And the ratio of the radius d of the opening 21 of the extruded housing 2 of this group of batteries to the radius D of the maximum cross-section perpendicular to the axis of the housing 2 of the accommodating space 22 is 11%, which is less than the minimum value of 20% of the above more optimal range. The appearance of this group of batteries is good, the sealing position is smooth and flat, and the airtightness detection also meets the requirements, but the distance between the flow guide pin 3 and the edge of the opening 21 of the housing 2 is too close, and there is a risk of short circuit to a certain extent. The overall yield is only greater than 95%.

[0050] For the battery in Comparative Example 3, the ratio of the necking depth a of the necking space 23 to the radius b of the maximum cross-section perpendicular to the axis of the housing 2 of the accommodating space 24 is 10%, slightly less than the minimum value of 12% of the above more optimal range. The appearance of this group of batteries is good, the sealing position is smooth and flat, the flow guide pin 3 coincides with the axis of the housing 2, but the value of the airtightness detection is slightly lower than the lower limit of the process parameters, and the overall yield is slightly lower, specifically greater than 97%.

[0051] For the battery in Comparative Example 4, the ratio of the necking depth a of the necking space 23 to the radius b of the maximum cross-section perpendicular to the axis of the housing 2 of the accommodating space 24 is 18%, slightly greater than the maximum value of 15% of the above more optimal range. The appearance of this group of batteries is good, the sealing position is smooth and flat, the flow guide pin 3 coincides with the axis of the housing 2, but the airtightness detection is unstable, there is a risk of liquid leakage, and there is a risk of neck breakage in the necking process. The overall yield is only greater than 85%.

[0052] For the battery of Comparative Example 5, the ratio E of the volume of the elastic ball 4 before extrusion to the volume after extrusion is 25%, which is less than the minimum value of 30% in the above more optimal range. The appearance of this group of batteries is good, the sealing position is smooth and flat, the diversion pin 3 coincides with the axis of the housing 2, but the compression of the elastic ball 4 is significantly insufficient, the value of the airtightness detection is on the lower limit of the process parameters, and the comprehensive yield is slightly low, specifically greater than 97%.

[0053] For the battery of Comparative Example 6, the ratio E of the volume of the elastic ball 4 before extrusion to the volume after extrusion is 72%, which is greater than the maximum value of 60% in the above more optimal range. The diversion pin 3 of this group of batteries coincides with the axis of the housing 2, and the airtightness detection meets the requirements, but there are wavy edges at the sealing position, the appearance is uneven, the force compression of the elastic ball 4 is too large, and the comprehensive yield is only greater than 92%.

[0054] It should be noted that the pressure P for the above airtightness detection is 0.65 ± 0.02 MPa.

[0055] As Figure 7 shown, optionally, when not extruded, the inner diameter of the housing 2 is basically the same as the outer diameter of the elastic ball 4, and the value range of the ratio of the height of the elastic ball 4 when not extruded to the overall height of the finished battery is 10% - 30%.

[0056] This battery uses the housing 2 directly as the positive electrode, eliminating the positive electrode tab welding process, improving production efficiency. The negative electrode uses the diversion pin 3, which can reduce the welding area with the negative electrode tab and realize the possibility of micro-battery process operation. And this battery eliminates the cap of the conventional micro-cylindrical lithium-ion battery, directly uses the housing 2 as the positive electrode output and the diversion pin 3 as the negative electrode output, and can be directly installed on special electrical appliances for use. In addition, by adopting the sealing method of one-time extrusion molding of the elastic ball 4, this battery can ensure the sealing performance while reducing the accuracy requirements of the rolling groove and sealing processes, reducing the processing difficulty, reducing the production cost, and improving the production efficiency.

[0057] As Figures 5-7 shown, this embodiment also provides a manufacturing method for manufacturing the above battery, and this manufacturing method includes processes such as processing the electrode sheets, inserting them into the housing, sealing, and forming.

[0058] Process of processing the electrode sheets: Mix and stir lithium nickel cobalt manganese oxide, conductive agent, binder and solvent, and apply them on both sides of the aluminum foil. After rolling and slitting, a positive electrode sheet is made. Mix and stir graphite, conductive agent, binder and solvent, and apply them on both sides of the copper foil. After rolling and slitting, a negative electrode sheet is made.

[0059] Processing and casing: The current collector 3 is welded to the second electrode plate, that is, the negative electrode plate. Then, the first electrode plate, the separator, and the second electrode plate with the current collector 3 are wound to form a core 1, and it is ensured that the first electrode plate is located on the outermost side to prepare for the subsequent contact conduction between the first electrode plate and the casing 2. After the core 1 is impregnated with the electrolyte, it is integrally installed into the casing 2. Optionally, the casing 2 is an aluminum casing.

[0060] The sealing process includes a necking process, assembling the elastic ball 4, and an extrusion process.

[0061] Necking process: A necking structure is processed on the casing 2 by using a hob extrusion process, so that a necking space 23 is formed inside the casing 2, and the concave inner wall can support the elastic ball 4 to prepare for the subsequent assembly of the elastic ball 4.

[0062] Assembling the elastic ball 4 process: The elastic ball 4 is sleeved on the current collector 3 and pushed into the casing 2.

[0063] Extrusion process: The casing 2 and the elastic ball 4 are extruded by a sealing die to form a seal.

[0064] Formation process: The battery is subjected to formation charge and discharge operations.

[0065] The battery obtained by applying the above manufacturing method has a higher qualified rate and production efficiency.

[0066] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the embodiments here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A battery, characterized in that The invention comprises a winding core (1), a shell (2), a guide needle (3) and an elastic ball (4); the shell (2) has an opening (21), a receiving space (22), a necking space (23) and a receiving space (24) which are connected in sequence; the elastic ball (4) and the shell (2) are squeezed, the shell (2) forms the receiving space (22); the elastic ball (4) is located at the receiving space (22) and blocks the opening (21); the winding core (1) is located in the receiving space (24); the outermost side of the winding core (1) is a first pole piece, the first pole piece abuts against the inner wall of the shell (2); one end of the guide needle (3) is inserted into the winding core (1) and connected to the second pole piece of the winding core (1); the other end of the guide needle (3) passes through the elastic ball (4) and is located outside the shell (2).

2. The battery according to claim 1, characterized in that The ratio E of the volume of the elastic ball (4) before extrusion to the volume after extrusion satisfies 30%≤E≤60%.

3. The battery according to claim 1, characterized in that The radius of the opening (21) of the shell (2) after extrusion is d, and the radius of the maximum cross section of the accommodating space (22) perpendicular to the axial direction of the shell (2) is D, satisfying 20%≤d / D≤40%.

4. The battery according to claim 1, characterized in that Along the axial direction of the shell (2), the vertical distance from the end of the shell (2) that is not squeezed and has the opening (21) to the end of the necked space (23) close to the opening (21) is A, and the overall height of the battery is B, satisfying 10%≤A / B≤15%.

5. The battery according to any one of claims 1 to 4, characterized in that: Along the radial direction of the shell (2), the necking depth of the necking space (23) is a, and the radius of the maximum cross section of the accommodating space (24) perpendicular to the axial direction of the shell (2) is b, satisfying 12%≤a / b≤15%.

6. The battery according to any one of claims 1 to 4, characterized in that: The guide needle (3) extends along the axial direction of the housing (2).

7. The battery according to any one of claims 1 to 4, characterized in that: The guide needle (3) is welded to the second pole piece.

8. The battery according to any one of claims 1 to 4, characterized in that: The first pole piece is a positive pole piece, and the second pole piece is a negative pole piece, or the first pole piece is a negative pole piece, and the second pole piece is a positive pole piece.

9. A manufacturing method, characterized in that: For manufacturing a battery as claimed in any one of claims 1 to 8, the manufacturing method comprises the following steps: Sealing process: processing a necking structure on the shell (2), sleeve the elastic ball (4) on the guide needle (3), push it into the shell (2), and squeeze the shell (2) and the elastic ball (4) to seal and form.

10. The manufacturing method according to claim 9, characterized in that: Before the sealing process, the method further comprises the following steps: Processing into the shell: welding the guide needle (3) to the second pole piece, winding the first pole piece, the diaphragm and the second pole piece with the guide needle (3) to form the winding core (1), and then placing the winding core (1) into the shell (2) after being soaked in electrolyte.

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