A battery core center hole pin assembly

Abstract

The present invention discloses a battery cell center hole pin assembly, comprising a housing, at least one lead conductor, and an insulating sealant. The assembly can be sealed with the battery cell housing to form an annular cavity. This cavity can accommodate a center hole electrode assembly, wherein the lead conductor has contact areas at both ends of the needle-like structure for circuit expansion. This composite pin assembly enables polarity separation of cylindrical battery cells within the center hole of the electrode assembly, overturning the original design of using the battery cell housing and cover as positive and negative electrodes. This frees up space in the cylindrical battery cell that would otherwise be used for the insulating housing and cover, thereby increasing the cell's energy density.

Description

Technical Field

[0001] The present invention relates to the technical field of battery core component structures, and in particular to a battery core center hole pin assembly. Background Art

[0002] Lithium-ion batteries are environmentally friendly, boasting long cycle life, excellent rate capability, and safety and reliability. They are widely used in energy storage products, consumer electronics, and power cell products. Lithium-ion batteries can be categorized by manufacturing process into soft-pack lithium-ion cells, prismatic aluminum-cased cells, and steel-cased cylindrical cells. Steel-cased cylindrical cells, due to their highly standardized manufacturing process and relatively low cost, are widely used in power vehicle batteries. As the rapidly developing new energy industry faces fierce market competition, customer requirements for battery cell energy density and appearance are increasing.

[0003] Currently, common lithium-ion battery electrode assembly forming processes include winding and lamination. Practice has proven that in the field of cylindrical batteries, the winding process achieves better battery space utilization and higher energy density than cells produced through the lamination process. However, when winding cylindrical electrode assemblies, a central hole is inevitably left behind due to the placement of the winding needle. This hole is generally larger than 1mm in diameter. This central hole wastes battery cell space and can also cause the electrode assembly to collapse during use. Therefore, most cylindrical cells place a pin in the central hole of the electrode assembly to stabilize the structure. The commonly used non-central hole pin is a metal tube.

[0004] Typically, a cylindrical battery cell consists of a U-shaped metal bottom shell and an I-shaped top cover. These two shells are sealed together with an insulating rubber ring and rolled edges, sealing the electrode assembly, which houses the center pin, within the cavity they create. In cylindrical cells with this structure, the center pin occupies the volume of the winding center hole and serves only to stabilize the electrode assembly structure. Furthermore, the cylindrical cell must provide additional space to implement the cell's electrical polarity separation function. For example, in traditional 18650 and 21700 cylindrical battery cells, the positive and negative poles of the battery cells are respectively connected to the bottom shell and the shell cover. The separation of positive and negative polarity is achieved by sealing the shell cover side with an insulating rubber ring through a rolling process. The above structure occupies about 4 to 6 mm of the battery cell length space, which is equivalent to 5.7% to 10% space waste; the above structure will sharply reduce the energy density when the battery cell height is reduced. Therefore, for cylindrical battery cells with smaller height (button batteries), the battery cell polarity separation function is currently transferred to the radial direction. The positive and negative poles of this type of battery cell are still connected to the bottom shell and the shell cover respectively. The bottom shell and the shell cover are coaxially buckled together, and an insulating layer is filled in the middle to achieve polarity separation. The polarity separation structure is in the outermost circle of the battery cell (reference patent: ZL201080007121.9). This structure requires about 0.6 mm of space on the outermost circle of the circular cross-section, which is equivalent to 6% to 15% space waste for battery cells with a diameter of 8 to 20 mm.

[0005] In summary, the current space distribution of cylindrical battery cells is unreasonable. The center pin and battery polarity separation each occupy a part of the battery cell volume, which hinders the improvement of the battery cell energy density. Summary of the Invention

[0006] The purpose of the present invention is to provide a battery cell center hole pin assembly, which not only has the functions of a traditional pin assembly, but also can realize the separation of battery cell polarity, and can release the original additional space used for battery cell polarity separation, thereby improving the battery cell energy density.

[0007] To achieve the purpose of the present invention, the present invention provides a battery core center hole pin assembly, comprising:

[0008] A pin housing, at least one lead conductor and an insulating sealing material;

[0009] Among them, the pin housing includes at least one cylindrical portion with upper and lower openings, and the cylindrical portion is inserted into the center hole of the electrode group; the insulating sealing material is partially or completely arranged in the cylindrical portion; the lead-out conductor passes through the insulating sealing material; the lower end of the lead-out conductor is conductively connected to the positive electrode and / or negative electrode of the battery cell, thereby realizing the polarity lead-out of the battery cell.

[0010] Furthermore, the longitudinal section of the pin housing is The invention discloses a type of cylindrical part, which comprises a cylindrical part with upper and lower openings and a disc-shaped flange formed by expanding outward at the top end of the cylindrical part.

[0011] Furthermore, the longitudinal section of the pin housing is The invention is a kind of circular cup which is shaped like a cylinder with upper and lower openings and a round cup which is expanded outwards at the top end of the cylinder.

[0012] Furthermore, the longitudinal section of the pin housing is Of course, the longitudinal section of the pin housing is not limited to the above three situations. The shape of the pin housing can be expanded outward from one end of the upper end of the columnar portion to form a A form between several forms.

[0013] Furthermore, the battery cell includes at least one positive electrode and one negative electrode and a separator separating the positive and negative electrodes. The positive electrode, negative electrode and separator are formed in a spiral winding manner around a central hole of an electrode group. The diameter of the central hole of the electrode group is greater than 0 and smaller than the diameter of the battery cell.

[0014] Furthermore, the battery core center hole pin assembly is used in conjunction with the battery core housing, and the two are sealed and connected to form an annular closed cavity capable of accommodating the electrode group.

[0015] Furthermore, the longitudinal section of the insulating sealing material is The pin housing comprises a cylindrical body inserted into the cylindrical portion of the pin housing and a flange formed by expanding outward from the bottom end of the cylindrical body to completely cover the lower end surface of the cylindrical portion of the pin housing.

[0016] Furthermore, it also includes at least one injection hole for injecting electrolyte into the battery core.

[0017] Furthermore, the liquid injection hole is provided on the pin housing and / or on the insulating sealing material.

[0018] Furthermore, the injection hole passes through the insulating sealing material up and down, and is arranged at the center or eccentric position of the insulating sealing material. The injection hole is sealed by a sealing member to prevent the electrolyte from leaking from the injection hole.

[0019] Furthermore, the sealing member adopts one of the following structures:

[0020] The first type: the seal adopts an end cap structure, which includes an end portion and an embedded portion arranged at the lower end of the end block, the end portion covers the upper end of the cylindrical portion, and the embedded portion is inserted into the cylindrical portion;

[0021] The second type: the sealing member is at least one steel ball, the steel ball is inserted into the cylindrical portion, and the steel ball and the cylindrical portion are interference fit.

[0022] Furthermore, the battery core center hole pin assembly is made of a material with waterproof properties.

[0023] Furthermore, the material with waterproof properties is a metal material or a non-metal material.

[0024] Furthermore, the metal material is stainless steel, aluminum or aluminum alloy.

[0025] Furthermore, the non-metallic material is ceramic or plastic.

[0026] Furthermore, the insulating sealing material is made of polypropylene.

[0027] Furthermore, the lead conductor is an aluminum sheet or a nickel sheet.

[0028] The battery cell center hole pin assembly of the present invention is preferably suitable for cylindrical lithium-ion battery cells, and has the ability to be sealed and connected to the battery cell shell to form an annular cavity. This cavity can accommodate the electrode group containing the center hole, wherein the lead-out conductor has contact areas for circuit expansion at its inner and outer ends respectively, and has the ability to be conductively connected to the positive electrode and / or negative electrode of the battery cell to realize the polarity lead-out of the battery cell.

[0029] The battery cell center hole pin assembly of the present invention can realize the function of a traditional pin, and is partially or completely inserted into the center hole of the battery cell wound electrode group. In order to realize the polarity lead-out of the battery cell, an insulating sealing material is provided in the cylindrical portion, and the lead-out conductor passes through the insulating sealing material up and down. This design allows the positive electrode and / or negative electrode inside the battery cell to lead out the polarity of the battery cell through the above-mentioned lead-out conductor, and the presence of the insulating sealing material enables the polarity separation of the battery cell to be realized in the battery cell center hole pin assembly, thereby avoiding the embarrassment of the traditional cylindrical battery cell being forced to occupy the limited space of the battery cell to realize the polarity separation of the battery cell. The insulating sealing material is generally made of plastic, and the injection molding process is preferably used to add the insulating sealing material to the inside of the cylindrical portion structure.

[0030] The battery cell center hole pin assembly implemented by the present invention is inevitably partially exposed to the battery cell usage environment because it needs to realize the battery cell polarity lead-out function. This is completely different from traditional pins, which are ultimately sealed in the battery cell shell together with the electrode group. Since part of the new battery cell center hole pin assembly is to be placed inside the electrode group and part is to be exposed to the battery cell usage environment, this requires that the new battery cell center hole pin assembly must have waterproof properties and the ability to expand to form a closed space, and the structure after expansion must meet the following characteristics: the surface originally corresponding to the pin and the electrode group always corresponds to the electrode group after expansion. In actual applications, the battery cell shell will complete this expansion function, so the new battery cell center hole pin assembly is designed to be sealed and connected to the battery cell shell to form an annular cavity. The present invention preferably pre-sets the injection hole on the insulating sealing material, or sets it in the center of the insulating sealing material or in an eccentric position. The injection hole will be sealed by a sealant after the injection is completed during the battery cell manufacturing process.

[0031] The battery cell center hole pin assembly implemented by the present invention has a battery cell polarity lead-out function that is achieved by presetting a lead-out conductor in the insulating sealing material of the cylindrical portion. The lead-out conductor must have contact areas at both ends of the needle-shaped body that can be used for circuit expansion. The contacts inside the corresponding battery cell are used to achieve conductive connection with the positive electrode and / or negative battery cell of the battery cell, and the contacts outside the corresponding battery cell are used to achieve conductive connection with an external power supply or a design interface. Usually, an aluminum sheet and a nickel sheet can be preset as lead-out conductors in the cylindrical portion. When assembling the battery cell, the positive electrode sheet of the battery cell is conductively connected to the above-mentioned aluminum sheet through a conductor or directly, and the negative electrode sheet of the battery cell is conductively connected to the above-mentioned nickel sheet through a conductor or directly. The aluminum sheet and the nickel sheet eventually become the positive and negative electrodes of the battery cell. In order to reduce the size of the cylindrical body, a metal sheet (such as an aluminum sheet or a nickel sheet) can also be preset. When assembling the battery cell, the positive electrode or negative electrode of the battery cell is conductively connected to the above-mentioned aluminum sheet through a conductor or directly, and a metal (such as stainless steel) battery cell shell is used to conductively connect the negative electrode of the battery cell to the metal shell. The aluminum sheet is the positive electrode of the battery cell, and the metal shell is the negative electrode of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic structural diagram of Example 1 of the present invention;

[0033] Figure 2 This is a schematic structural diagram of Example 2 of the present invention;

[0034] Figure 3 This is a schematic structural diagram of Example 3 of the present invention;

[0035] Figure 4 This is a schematic structural diagram of Example 4 of the present invention;

[0036] Figure 5 This is a schematic structural diagram of Example 5 of the present invention;

[0037] Figure 6 This is a schematic diagram of the first structure of the sealing member in the present invention;

[0038] Figure 7 This is a schematic diagram of the second structure of the sealing member in the present invention;

[0039] Figure 8 This is a schematic diagram of the first structure of the present invention applied to a battery cell;

[0040] Figure 9 This is a schematic diagram of the second structure of the present invention applied to a battery cell. DETAILED DESCRIPTION

[0041] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0043] Example 1

[0044] like Figure 1 As shown, this embodiment discloses a battery core center hole pin assembly 100A including:

[0045] A pin housing 101, a positive electrode lead conductor 103, a negative electrode lead conductor 104, and an insulating sealing material 102;

[0046] The longitudinal section of the pin housing 101 is The device is a type of device comprising a cylindrical portion with upper and lower openings and a disc-shaped flange extending outward from the top of the cylindrical portion. The cylindrical portion is inserted into the central hole of the electrode assembly; the insulating sealant 102 is partially disposed within the cylindrical portion; the positive electrode lead conductor 103 and the negative electrode lead conductor 104 extend through the insulating sealant; the lower ends of the positive electrode lead conductor 103 and the negative electrode lead conductor 104 are electrically connected to the positive and / or negative electrodes of the battery cell, thereby achieving cell polarity extraction.

[0047] The longitudinal section of the insulating sealing material 102 is The pin housing 101 is shaped and includes a column inserted into the cylindrical portion of the pin housing 101 and a flange formed by expanding outward from the bottom end of the column to completely cover the lower end surface of the cylindrical portion of the pin housing 101.

[0048] The positive electrode lead conductor 103 and the negative electrode lead conductor 104 are made of aluminum sheets or nickel sheets.

[0049] The insulating sealing material 102 is provided with a liquid injection hole, which passes through the insulating sealing material up and down and is provided at the center or eccentric position of the insulating sealing material.

[0050] It should be noted that the dimensions of the battery cell center hole pin assembly 100A and the lead conductor in this application can be known by those skilled in the art through conventional techniques, and will not be described in detail.

[0051] During processing, the lower ends of the positive electrode lead-out conductor 103 and the negative electrode lead-out conductor 104 extend beyond the cylindrical portion of the pin housing 101, and the upper ends extend beyond the disc-shaped flange. The cylindrical portion is injected with an insulating sealing material 102 by template injection molding. Preferably, the insulating sealing material 102 is made of polypropylene plastic, and finally the positive electrode lead-out conductor 103 and the negative electrode lead-out conductor 104 in the cylindrical portion are completely wrapped. At the same time, a through hole is formed in the center or eccentricity of the tube, which is the liquid injection hole. The outer wall of the insulating sealing material 102 is tightly combined with the inner wall of the cylindrical portion, and the positive electrode lead-out conductor 103 and the negative electrode lead-out conductor 104 are symmetrically located in the insulating sealing material 102.

[0052] Example 2

[0053] This embodiment is an improvement based on the embodiment 1. The only difference between this embodiment and the embodiment 1 is the pin housing 101 . The rest of the structure is the same as that of the embodiment 1.

[0054] In this embodiment, if Figure 2 As shown, the longitudinal section of the pin housing 101 of the battery core center hole pin assembly 100B provided in this embodiment is The invention is a kind of circular cup which is shaped like a cylinder with upper and lower openings and a round cup which is expanded outwards at the top end of the cylinder.

[0055] Example 3

[0056] This embodiment is an improvement based on Embodiment 1 and Embodiment 2. The only difference between this embodiment and Embodiment 1 and Embodiment 2 is the pin housing 101 . The rest of the structure is the same as that of Embodiment 1.

[0057] In this embodiment, Figure 3 As shown, the longitudinal section of the pin housing 101 of the battery core center hole pin assembly 100C provided in this embodiment is Shape, which is a cylindrical part with upper and lower openings.

[0058] Example 4

[0059] This embodiment is an improvement based on the embodiment 1. The difference between the battery core center hole pin assembly 100D provided in this embodiment and the embodiment 1 is that the insulating sealing material 102 is not provided with a liquid injection hole. The rest of the structure is the same as that of the embodiment 1. Figure 4 Of course, in the second and third embodiments, the insulating sealing material 102 may not be provided with a liquid injection hole, and the liquid injection hole may be provided at other positions.

[0060] Example 5

[0061] This embodiment is an improvement based on the embodiment 1. The difference between the battery core center hole pin assembly provided in this embodiment and the embodiment 1 is only that, Figure 5 As shown, there is only one lead conductor 103, and this lead conductor 103 can be a positive electrode lead conductor or a negative electrode lead conductor.

[0062] Of course, this improvement can be made in Embodiment 2, Embodiment 3, and Embodiment 4, and only one lead conductor 103 is provided, which will not be described in detail here.

[0063] It should be noted that in Examples 1, 2, 3, and 5, the injection hole is provided on the insulating sealing material 102. Since the injection hole needs to be sealed with a sealant after use, the structure of the sealant adopts one of the following structures:

[0064] The first one: Figure 6 As shown, the seal adopts an end cap structure, which includes an end portion and an embedded portion arranged at the lower end of the end block, the end portion covers the upper end of the cylindrical portion, and the embedded portion is inserted into the cylindrical portion;

[0065] The second type: Figure 7 As shown, the sealing member is at least one steel ball, which is inserted into the cylindrical portion and has an interference fit with the cylindrical portion.

[0066] It should be noted that

[0067] The longitudinal section of the battery cell housing used in conjunction with the structure of the pin housing in Example 1 is U-shaped, and both the pin housing and the battery cell housing can be an integrally formed structure or a multi-part spliced ​​structure.

[0068] The longitudinal section of the cell housing used in conjunction with the structure of the pin housing in Example 2 is in the shape of a straight line, and both the pin housing and the cell housing can be an integrally formed structure or a multi-part spliced ​​structure.

[0069] The longitudinal section of the battery cell housing used in conjunction with the structure of the pin housing in Example 3 is shape, and the pin housing and the battery cell housing can be an integrally formed structure or a multi-part splicing structure.

[0070] The above-mentioned pin housing is used in conjunction with the battery cell housing, and the two are sealed and connected to form an annular closed cavity that can accommodate the electrode group.

[0071] In addition, the battery core center hole pin assembly is made of a waterproof material, which includes a metal material or a non-metal material. Preferably, the metal material is stainless steel, aluminum, or an aluminum alloy; the non-metal material is ceramic or plastic.

[0072] In addition, such as,8, Figure 9 FIG. 1 shows an example structure of an application of Example 1 of the present invention in a battery cell, wherein the lower ends of the positive electrode lead conductor 103 and the negative electrode lead conductor 104 are conductively connected to the positive electrode and the negative electrode, respectively, in two ways:

[0073] The first one: Figure 8 The lower end of the electrode lead conductor is welded to one end of the transition conductor, and the other end of the transition conductor is welded to the positive electrode or the negative electrode;

[0074] The second type: Figure 9 The lower end of the electrode lead conductor is directly welded to the positive electrode or the negative electrode.

[0075] The battery cell in the figure includes at least one positive electrode 201 and one negative electrode 202 and a separator 203 separating the positive and negative electrodes. The positive electrode 201, the negative electrode 202 and the separator 203 are formed in a spiral winding manner around a central hole of an electrode group. The diameter of the central hole of the electrode group 200 is greater than 0 and smaller than the diameter of the battery cell.

[0076] A layer of insulating tape 300 - a is laid on the inner side of the bottom end of the battery cell casing 300 to prevent a short circuit between the positive electrode lead conductor 103 and the negative electrode lead conductor 104 and the battery cell casing 300 , and also to prevent a short circuit between the positive electrode transition conductor 204 and the negative electrode transition conductor 205 and the battery cell casing 300 .

[0077] During assembly, insulating sealing material 102 is injected into the pin housing 101 using a molded injection molding method, ultimately completely encapsulating the positive electrode lead conductor 103 and the negative electrode lead conductor 104 within the cylindrical portion. A longitudinal injection hole 400 is formed in the insulating sealing material 102, which is sealed with a sealant 400-a. The insulating sealing material 102 is tightly bonded to the inner wall of the cylindrical portion. The cylindrical portion is inserted into the center hole of the electrode assembly. The positive electrode lead conductor 103 and the negative electrode lead conductor 104 are then bent outward and welded to the positive electrode transition conductor (positive electrode tab) 204 and the negative electrode transition conductor (negative electrode tab) 205, respectively. A matching battery cell housing is used, and the connection between the pin housing and the battery cell housing is sealed by laser welding. Electrolyte is then injected into the battery cell through the injection hole 400 reserved in the insulating sealing material 102. After injection, the injection hole 400 is sealed. After completing the above operations, the battery cell undergoes conventional formation treatment to form a secondary lithium-ion cylindrical battery cell. The battery cell center hole pin assembly achieves insulation and lead-out of the positive and negative polarities of the battery cell. The positive electrode lead-out conductor 103 is the positive electrode of the battery cell, and the negative electrode lead-out conductor 104 is the negative electrode of the battery cell, avoiding the need to separate the polarity of the battery cell by occupying space in the height or diameter direction.

[0078] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A battery core center hole pin assembly, characterized in that: include: A pin housing, a positive electrode lead conductor, a negative electrode lead conductor, and an insulating sealing material; The pin housing includes at least one cylindrical portion with upper and lower openings, which is inserted into the center hole of the electrode group; the insulating sealing material is partially or completely disposed within the cylindrical portion; the positive electrode lead conductor and the negative electrode lead conductor pass through the insulating sealing material; the lower ends of the positive electrode lead conductor and the negative electrode lead conductor are respectively conductively connected to the positive electrode and the negative electrode of the battery cell, thereby realizing the polarity lead of the battery cell; The battery core center hole pin assembly is used in conjunction with the battery core housing, and the two are sealed to form an annular closed cavity capable of accommodating the electrode group; The pin housing adopts one of the following structures: First: the longitudinal section of the pin housing is The shape comprises a cylindrical portion with upper and lower openings and a disc-shaped flange formed by expanding outward from the top end of the cylindrical portion; The longitudinal section of the second pin housing is The shape comprises a cylindrical portion with upper and lower openings and a round cup formed by expanding outward from the top end of the cylindrical portion; Third: The longitudinal section of the pin housing is in the shape of "||", which is a cylindrical portion with upper and lower openings.

2. The battery core center hole pin assembly according to claim 1, characterized in that: The battery cell includes at least one positive electrode and one negative electrode and a separator separating the positive and negative electrodes. The positive electrode, negative electrode and separator are formed in a spiral winding manner around a central hole of an electrode group. The diameter of the central hole of the electrode group is greater than 0 and smaller than the diameter of the battery cell.

3. The battery core center hole pin assembly according to claim 1, characterized in that: The longitudinal section of the insulating sealing material is The pin housing comprises a cylindrical body inserted into the cylindrical portion of the pin housing and a flange formed by expanding outward from the bottom end of the cylindrical body to completely cover the lower end surface of the cylindrical portion of the pin housing.

4. The battery core center hole pin assembly according to claim 1, characterized in that: It also includes at least one injection hole for injecting electrolyte into the battery core.

5. The battery core center hole pin assembly according to claim 4, characterized in that: The injection hole is arranged on the pin housing and / or on the insulating sealing material.

6. The battery core center hole pin assembly according to claim 5, characterized in that: The injection hole passes through the insulating sealing material up and down, and is arranged at the center or eccentric position of the insulating sealing material. The injection hole is sealed by a sealing member to prevent the electrolyte from leaking from the injection hole.

7. The battery core center hole pin assembly according to claim 6, characterized in that: The sealing member adopts one of the following structures: The first type: the seal adopts an end cap structure, which includes an end portion and an embedded portion arranged at the lower end of the end block, the end portion covers the upper end of the cylindrical portion, and the embedded portion is inserted into the cylindrical portion; The second type: the sealing member is at least one steel ball, the steel ball is inserted into the cylindrical portion, and the steel ball and the cylindrical portion are interference fit.

8. The battery core center hole pin assembly according to claim 7, characterized in that: The battery core center hole pin assembly is made of a material with waterproof properties.

9. The battery core center hole pin assembly according to claim 8, characterized in that: The material with waterproof properties is a metal material or a non-metal material.

10. The battery core center hole pin assembly according to claim 9, characterized in that: The metal material is stainless steel, aluminum or aluminum alloy.

11. The battery core center hole pin assembly according to claim 9, characterized in that: The non-metal material is ceramic or plastic.

12. The battery core center hole pin assembly according to claim 1, characterized in that: The insulating sealing material is made of polypropylene.

13. The battery core center hole pin assembly according to claim 1, characterized in that: The positive electrode lead conductor and the negative electrode lead conductor are aluminum sheets or nickel sheets.

Images