Battery housing assembly, welding fixture and welding method

Abstract

The application relates to a battery shell assembly, a welding clamp and a welding method. The welding method comprises the following steps: providing an electrode assembly and a shell, the electrode assembly comprising a sleeve and a pole column located in the sleeve, the sleeve and the pole column being connected through glass ring sealing, the sleeve comprising a barrel, one end of the barrel being provided with a flange, the shell comprising a first side plate, the first side plate being provided with a mounting hole; clamping and positioning the electrode assembly and the first side plate through a welding tool, so that the barrel is inserted into the mounting hole, and the flange is attached to the first side plate; and welding the flange on the first side plate, so as to form a ring-shaped welding mark at the connection between the flange and the first side plate. The application further discloses a battery shell assembly and a welding clamp. The application can improve the reliability and safety of the battery shell assembly.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a battery casing assembly and welding method. Background Technology

[0002] Battery casing assemblies generally consist of a casing and electrode assemblies, which electrically connect the internal battery cells and external electrical components. The electrode assemblies are typically fixed to the casing using a riveting process. Each electrode assembly includes terminals, and an insulating component is required between the terminals and the casing to ensure a tight seal. Plastic sheets are commonly used as these insulating components. However, plastic components have low temperature resistance and poor corrosion resistance, making them prone to failure under thermal disturbances, humidity, or long-term mechanical stress, thus affecting the sealing and insulation performance of the battery casing. This makes it difficult to meet the safety requirements of batteries under high-power charging and discharging conditions and the needs for long-term safety. Furthermore, the riveting process is highly dependent on equipment precision and material properties, making it difficult to guarantee product yield and production efficiency. Micro-cracks or pressure marks can easily occur during riveting, leading to a decrease in the insulation performance between the terminals and the casing. The riveted structure also cannot guarantee long-term stable mechanical strength and is prone to failure under drop or thermal cycling conditions. Therefore, casing assemblies assembled using existing plastic riveting encapsulation methods cannot guarantee the reliability and safety requirements of the product. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to improve the reliability and safety of battery casing components in the prior art.

[0004] To solve the above-mentioned technical problems, the present invention provides a welding method for a battery casing assembly, comprising:

[0005] An electrode assembly and a housing are provided. The electrode assembly includes a sleeve and an electrode post located inside the sleeve. The sleeve and the electrode post are sealed together by a glass ring. The sleeve includes a cylindrical body with a flanged flange at one end. The housing includes a first side plate with mounting holes.

[0006] The electrode assembly and the first side plate are clamped and positioned using welding fixtures, so that the cylinder is inserted into the mounting hole and the flange is fitted with the first side plate.

[0007] The flange is welded to the first side plate to form an annular weld mark at the connection between the flange and the first side plate.

[0008] In one embodiment of the present invention, the flange is welded to the first side plate using a segmented welding method, the segmented welding method including...

[0009] Multiple welding positions are preset at the connection between the flange and the first side plate. All the welding positions are arranged in a ring. During welding, each welding position is welded sequentially, and there is a preset time interval between the welding times of two adjacent welding positions.

[0010] In one embodiment of the present invention, the total number of welding positions is 4 to 16 segments, and the segmented welding method includes numbering all the welding positions sequentially from 1 to N, where N is a natural number greater than 1, welding is performed first at the odd-numbered welding positions, and then welding is performed at the even-numbered welding positions; or, welding is performed first at the even-numbered welding positions, and then welding is performed at the odd-numbered welding positions.

[0011] In one embodiment of the present invention, the area of ​​the first side plate located around the annular weld mark constitutes a non-welding area, which is connected by a heat insulation component and a welding fixture.

[0012] In one embodiment of the present invention, a cooling channel is provided inside the welding fixture. During the process of welding the flange to the first side plate, coolant is circulated in the cooling channel. The flow rate of the coolant is 0.2 to 5 L / min, and the temperature of the coolant when it enters the cooling channel is 5 to 40°C.

[0013] In one embodiment of the present invention, the flange is welded to the first side plate using a pulsed laser welding method. The laser wavelength used in the pulsed laser welding method is 1000-1100 nm, the pulse width is 0.5-10 ms, the single pulse energy is 0.05-2.0 J, and the spot diameter is 0.1-0.6 mm.

[0014] In one embodiment of the present invention, when the flange is welded to the first side plate, a pulse hot press welding method is used. The welding pressure of the pulse hot press welding method is 5 to 50 N, the peak heating temperature (maximum value) is 200 to 450°C, and the heating time is 0.1 to 2 s.

[0015] The present invention also discloses a welding fixture for welding a battery casing assembly as described in any of the above claims. The welding fixture includes a first clamping member and a second clamping member. The flanged flange and the first side plate are attached to each other and clamped between the first clamping member and the second clamping member. The first clamping member has a first through hole in its middle portion. The area on the first side plate for welding with the flanged flange is exposed in the first through hole.

[0016] In one embodiment of the present invention, the first clamping member is provided with a slot, and a heat insulation member is provided in the slot. The area of ​​the first side plate located outside the annular weld mark constitutes a non-welded area, and the heat insulation member is in contact with the non-welded area.

[0017] In one embodiment of the invention, the thermal conductivity of the insulation element is less than 10 W / (m·K).

[0018] In one embodiment of the present invention, a cooling channel is provided inside the second clamping member for the flow of coolant.

[0019] In one embodiment of the present invention, the first clamping member and the second clamping member are connected by a guide post. The first clamping member is provided with a first positioning hole, and the second clamping member is provided with a second positioning hole. The guide post passes through the first positioning hole and the second positioning hole in sequence.

[0020] The present invention also discloses a battery casing assembly, which is manufactured by any of the welding methods described above. The battery casing assembly includes a housing and an electrode assembly. The electrode assembly includes a sleeve and an electrode post located inside the sleeve. The sleeve and the electrode post are sealed together by a glass ring. The sleeve includes a cylindrical body, and a flange is formed at one end of the cylindrical body. The housing includes a first side plate, and a mounting hole is provided on the first side plate. The cylindrical body is inserted into the mounting hole. The flange and the first side plate are welded together, and an annular weld mark is formed at the connection between the flange and the first side plate.

[0021] In one embodiment of the present invention, the width of the flange is 0.2 to 0.5 mm.

[0022] The technical solution of the present invention has the following advantages compared with the prior art:

[0023] The welding method described in this invention can effectively control the welding energy input and heat transfer path, block the conduction of heat to the glass ring, and effectively avoid sealing failure while ensuring welding strength, thereby effectively ensuring the airtightness, reliability and safety of the welded battery casing assembly. Attached Figure Description

[0024] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0025] Figure 1 This is a schematic diagram of the battery casing assembly of the present invention;

[0026] Figure 2 yes Figure 1The diagram shows a structural schematic of the battery casing assembly from another angle.

[0027] Figure 3 yes Figure 1 The exploded view of the battery casing assembly shown;

[0028] Figure 4 yes Figure 1 Side view of the battery housing assembly shown;

[0029] Figure 5 yes Figure 4 A magnified view of a section at point M1;

[0030] Figure 6 yes Figure 4 Sectional view at point BB;

[0031] Figure 7 yes Figure 6 A magnified view of a section at point M2;

[0032] Figure 8 This is a schematic diagram of the electrode assembly of the present invention;

[0033] Figure 9 yes Figure 8 Another structural schematic diagram of the middle electrode assembly;

[0034] Figure 10 yes Figure 8 Top view of the middle electrode assembly;

[0035] Figure 11 yes Figure 10 Sectional view at point AA;

[0036] Figure 12 This is a schematic diagram of the welding fixture in this invention;

[0037] Explanation of reference numerals on the accompanying drawings:

[0038] 10. Electrode assembly; 101. Electrode post; 102. Glass ring; 103. Sleeve; 1031. Cylinder body; 1032. Flanged flange;

[0039] 20. Housing; 201. First side plate; 2011. Mounting hole; 2012. Non-welded area; 2023. Circumferential weld mark; 202. Base plate;

[0040] 30. Welding fixture; 301. First clamping component; 3011. First through hole; 3012. Slot; 3013. First positioning hole; 302. Second clamping component; 3021. Cooling channel; 3022. Liquid inlet; 3023. Liquid outlet; 3024. Second positioning hole; 303. Heat insulation component; 304. Guide post;

[0041] 40. Laser head; Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present disclosure or its application or use.

[0043] In the description of this invention, it should be understood that the terms "vertical," "upper," "lower," "top," "side," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0044] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] Example 1

[0046] This embodiment discloses a welding method for a battery casing assembly, including the following steps:

[0047] Step 1: Provide electrode assembly 10 and housing 20;

[0048] Among them, see Figures 8-11 The electrode assembly 10 includes a sleeve 103 and an electrode post 101 located inside the sleeve 103. The sleeve 103 and the electrode post 101 are sealed together by a glass ring 102 (sealed connection).

[0049] The sleeve 103 includes a cylinder 1031, one end of which is formed with a flange 1032. The housing 20 includes a first side plate 201, and a mounting hole 2011 is provided on the first side plate 201.

[0050] Step 2: Use welding fixture 30 to clamp and position electrode assembly 10 and first side plate 201. After positioning, insert cylinder 1031 into mounting hole 2011 and make flange 1032 fit against first side plate 201.

[0051] Step 3, refer to Figures 1-7 The flange 1032 is welded to the first side plate 201 to form an annular weld mark 2023 at the connection between the flange 1032 and the first side plate 201.

[0052] In the aforementioned electrode assembly 10, the sleeve 103 and the inner electrode post 101 are sealed together by a glass ring 102, which can effectively ensure the insulation and airtightness between the sleeve 103 and the electrode post 101. During the preparation, glass material can be filled inside the sleeve 103 and the electrode post 101 and melted at high temperature, thereby connecting the sleeve 103 and the electrode post 101 together by hot-melt glass sealing to form an airtight structure.

[0053] The glass ring 102 has good high temperature resistance and airtightness, and can ensure the reliability of the connection structure even after long-term use.

[0054] The flange 1032 has the following functions during the welding process: first, it serves as a thermal buffer zone for the weld, effectively dispersing welding stress; second, it improves the alignment and positioning accuracy of the weld, avoiding welding misalignment caused by the deformation of thin material; and third, it enhances the mechanical bonding strength between the weld and the edge of the shell 20, thereby improving the sealing performance and reliability of the overall structure.

[0055] By adopting the electrode assembly 10 with the above structure and fixing the electrode assembly 10 and the housing 20 by welding the flange 1032 and the housing 20, it has obvious advantages in reducing welding deformation, improving welding stability and extending battery packaging life. It can effectively improve the airtightness and reliability of the battery housing assembly, and also facilitates the improvement of mass production assembly efficiency.

[0056] In some ways, see Figures 4-5 The aforementioned annular weld mark 2023 is a continuous weld mark, that is, the weld mark is a continuous annular structure, which better ensures the connection and sealing effect.

[0057] In some designs, the sleeve is made of 316L stainless steel. Both the 102 glass ring and 316L stainless steel can withstand temperatures above 200°C, which can effectively prevent failure caused by high temperatures.

[0058] In some embodiments, the flange 1032 is welded to the first side plate 201 using a segmented welding method, which includes:

[0059] Multiple welding positions are preset at the connection between the flange 1032 and the first side plate 201. All the welding positions are arranged in a ring. During welding, each welding position is welded sequentially. There is a preset time interval between the welding times of two adjacent welding positions. That is, after welding at a welding position, a preset time interval is required for short-term natural cooling (or forced cooling) until the local temperature returns to a safe threshold before welding the next adjacent welding position is carried out to reduce the heat accumulation effect.

[0060] For example, the preset time interval is 1 to 10 seconds to ensure that the local temperature drops back to the set threshold.

[0061] Furthermore, the total number of welding positions is 4 to 16 segments. The segmented welding method includes: numbering all welding positions sequentially from 1 to N, where N is a natural number greater than 1; welding is performed first at odd-numbered welding positions and then at even-numbered welding positions; or welding is performed first at even-numbered welding positions and then at odd-numbered welding positions.

[0062] Understandably, in some other methods, there may also be several welding positions between two adjacent welding operations.

[0063] In practice, the total number of welding positions can be 8, 12, or 16 segments, etc. After completing one round, reinforcing welds can be performed, or a two-round segmented welding strategy can be adopted: welding every segment in the first round, and filling in the gaps in the second round. The welding speed can range from 5 to 200 mm / s.

[0064] During the welding of this prefabricated electrode assembly to the housing, welding energy is transferred to the glass ring through the flange. If the heat input or heat transfer path cannot be effectively controlled, the annealed state of the glass ring can be damaged, leading to cracks or loss of airtightness. Simultaneously, housing deformation or poor weld quality can also affect overall reliability. Therefore, a welding method is needed that minimizes the thermal impact on the glass ring and electrode while ensuring welding strength and airtightness. The segmented welding method described above achieves segmented / time-based welding, ensuring localized, targeted heating. This localizes and shortens the welding energy exposure, significantly reducing the thermal impact on the sealing glass and electrode. It effectively controls the welding energy input and heat transfer path, thus ensuring the mechanical strength and airtightness of the weld while effectively limiting the thermal impact on the glass ring, electrode, and glass-metal interface within a safe window, reducing the risk of glass cracking or seal failure.

[0065] In some implementations, see Figure 12 The area of ​​the first side plate 201 located around the annular weld mark 2023 constitutes the non-welding area 2012. The non-welding area 2012 is connected to the welding fixture 30 through the heat insulation component 303 so that the heat flow can be guided and the heat can be dispersed through the heat insulation component 303 during welding, thereby protecting the structural integrity of the glass ring 102.

[0066] The aforementioned heat insulation component 303 can be a ceramic component or a heat insulation component 303 made of composite heat insulation material.

[0067] In some implementations, see Figure 12 The welding fixture 30 is equipped with a cooling channel 3021. During the welding of the flange 1032 to the first side plate 201, coolant is circulated in the cooling channel 3021. The flow rate of the coolant is 0.2 to 5 L / min, or more specifically, 0.5 to 3 L / min. The temperature of the coolant when it enters the inlet 3022 of the cooling channel 3021 is 5 to 40°C, or more specifically, 10 to 30°C, for example, 15°C.

[0068] By circulating the coolant, the temperature rise at the flange 1032 in the welding area can be controlled, ensuring that the temperature at the flange 1032 during welding never exceeds the critical annealing temperature of the glass ring 102, thus preventing softening of the glass ring 102. For example, if the glass softening temperature is X°C and the outer surface temperature of the glass ring 102 is Y°C, then the temperature should be controlled during welding to ensure that Y... <X。

[0069] Furthermore, the aforementioned cooling channel 3021 can adopt a microchannel copper block structure, that is, micron-level channels are set inside the copper block, which has high heat dissipation performance.

[0070] During welding, the liquid cooling provided by the cooling channel 3021, combined with the thermal isolation effect of the heat insulation component 303, can better block the conduction of welding heat to the sealing glass ring 102, thereby ensuring that the sealed connection between the sleeve 103 and the pole 101 in the electrode assembly is always unaffected.

[0071] In some embodiments, pulsed laser welding can be used when welding the flange 1032 onto the first side plate 201. The laser wavelength used in pulsed laser welding is 1000–1100 nm, the pulse width is 0.5–10 ms, the single pulse energy is 0.05–2.0 J, and the laser spot diameter is 0.1–0.6 mm. Additionally, the peak power is 50–250 W (pulse peak); the average power can be 5–30 W, and the pulse frequency is 1–50 Hz.

[0072] In practical implementation, pulsed laser deep penetration welding can be used, and single-mode laser (single-mode 14um fiber core laser), long collimation, and large focusing optical devices can be selected to effectively control the heat-affected zone and have a stable high-quality beam output. The welding energy can be strictly limited to the vicinity of the flange, avoiding heat transfer to the glass ring and electrode, thereby ensuring sealing performance and long-term reliability.

[0073] In other embodiments, the flange 1032 is welded to the first side plate 201 using a pulse thermocompression welding method. The pulse thermocompression welding method involves a welding pressure of 5–50 N, a peak heating temperature of 200–450°C, and a heating time of 0.1–2 s. For example, the pulse thermocompression welding method may involve a welding pressure of 10–30 N, a peak heating temperature of 300–380°C, and a heating time of 0.5–1 s.

[0074] During pulse hot press welding, a groove can be provided in the welding area of ​​the first side plate 201 of the housing 20, and a low melting point metal gasket (such as AuSn or other brazing filler metal) can be provided in the groove, so that the first side plate 201 and the flange 1032 are welded together by the low melting point metal gasket to reduce heat input; the groove can be a U-shaped groove, the depth of which can be 0.05 to 0.2 mm and the width can be 0.1 to 0.4 mm.

[0075] In some methods, the thickness of the low-melting-point metal gasket can be 0.02 to 0.1 mm.

[0076] Understandably, other welding methods (such as brazing) can also be used to weld the flange 1032 onto the first side plate 201.

[0077] During the welding process, thermocouples or infrared thermometers can be used to monitor the temperature on the back of the flange in real time. If the temperature exceeds the upper limit, welding should be suspended and the cooling intensity increased.

[0078] In some implementations, to better control temperature and avoid oxidation, an inert gas or local vacuum environment can be created around the welding fixture and welding area during welding, thereby improving the flow of the molten pool and reducing surface welding defects.

[0079] For example, a transparent vacuum hood is provided on the welding fixture 30, and an air extraction port is provided on the clamping fixture to achieve vacuum treatment. Alternatively, an inert gas is used to protect the flange welding area during welding. The inert gas can be argon or nitrogen, and the inert gas flow rate is 0.1 to 10 L / min.

[0080] After welding, helium mass spectrometry leak detection or differential pressure leak detection must be performed, with a leak detection sensitivity not exceeding [value missing]. .

[0081] In addition, after welding is completed, non-destructive testing of air tightness and electrical insulation is required.

[0082] The above non-destructive testing includes: first, visual inspection (cracks, solder balls, lack of fusion), then helium mass spectrometry leak detection or differential pressure leak detection, and electrical insulation measurement (insulation withstand voltage / leakage current is measured between the pole and the sleeve / shell under 500V DC current; if it is less than 1μA, it is qualified). If it is unqualified, it can be partially repaired by welding or reworked and scrapped.

[0083] The specific order can be: visual inspection (visual or automated vision); helium mass spectrometry / differential pressure leak detection; dielectric strength / insulation resistance testing; mechanical pull-out / shear sampling; thermal cycling / damp heat testing sampling.

[0084] The above welding method, through the combination of the segmented welding method and the coolant / thermal isolation structure, can maximize the control of welding energy input and heat transfer path, and block the conduction of heat to the glass ring. While ensuring the mechanical strength of the weld, it controls the thermal impact on the glass ring and metal pole in the electrode assembly within a safe threshold, thereby effectively avoiding sealing failure, ensuring the airtightness and long-term reliability after welding, and meeting the efficiency and consistency requirements of mass production assembly.

[0085] Example 2

[0086] See Figure 12 This embodiment discloses a welding fixture 30 for use in the welding method of the battery casing assembly described in Embodiment 1.

[0087] The welding fixture 30 includes a first clamping member 301 and a second clamping member 302. The flange 1032 and the first side plate 201 are attached together and clamped between the first clamping member 301 and the second clamping member 302. The first clamping member 301 has a first through hole 3011 in the middle. The area on the first side plate 201 that is used to weld with the flange 1032 is exposed in the first through hole 3011 to facilitate welding. For example, when laser welding is used, the laser beam emitted by the laser head 40 is directed to the welding area through the first through hole 3011.

[0088] Furthermore, the upper part of the first through hole 3011 is tapered.

[0089] In some embodiments, the first clamping member 301 is provided with a slot 3012, and a heat insulation member 303 is provided in the slot 3012. The area of ​​the first side plate 201 located outside the annular weld mark 2023 constitutes a non-welded area 2012. The heat insulation member 303 is in contact with the non-welded area 2012 to reduce the transfer of heat between the non-welded area 2012 and the clamp.

[0090] The aforementioned heat insulation component 303 and the first clamping component 301 are detachably connected, and can be attached before welding and removed after welding.

[0091] In some embodiments, the thermal conductivity of the insulation element 303 is less than 10 W / (m·K), and further, the thermal conductivity of the insulation element 303 is less than 5 W / (m·K).

[0092] The aforementioned heat insulation component 303 can be a ceramic component or a heat insulation component 303 made of composite heat insulation material.

[0093] In some embodiments, a cooling channel 3021 is provided inside the second clamping member 302 for coolant flow.

[0094] Coolant flows in from the inlet 3022 of the cooling channel 3021 and flows out from the outlet 3023.

[0095] Furthermore, the aforementioned cooling channel 3021 can adopt a microchannel copper block structure, that is, micron-level channels are set inside the copper block, which has high heat dissipation performance.

[0096] Understandably, the cooling area of ​​the cooling channel 3021 should ideally be located near one end of the flange 1032 to facilitate timely heat dissipation and prevent heat conduction to the glass ring.

[0097] In some embodiments, the first clamping member 301 and the second clamping member 302 are connected by a guide post 304. The first clamping member 301 is provided with a first positioning hole 3013, and the second clamping member 302 is provided with a second positioning hole 3024. The guide post 304 passes through the first positioning hole 3013 and the second positioning hole 3024 in sequence, thereby ensuring the accuracy of docking between the two clamping members.

[0098] Furthermore, the top of the guide post 304 is arc-shaped to facilitate the guide post's insertion / exit from the positioning hole, thereby improving positioning reliability and efficiency.

[0099] When using the above-mentioned welding fixture 30, first insert the cylinder 1031 of the electrode assembly 10 into the mounting hole 2011 of the first side plate 201, and make the flange 1032 contact the first side plate 201. Then, the structure formed by the flange 1032 and the first side plate 201 is clamped by the first clamping member 301 and the second clamping member 302, and a pre-tightening force is applied to the first clamping member 301 so that the contact surface between the flange 1032 and the first side plate 201 remains flat and slightly pressed (for example, the contact surface has a uniformly distributed force of 2 to 10 N, which can be set according to the area and material thickness of the flange 1).

[0100] Example 3

[0101] This embodiment discloses a battery casing assembly, which can be manufactured using the welding method described in Embodiment 1. (See reference...) Figures 1-7 The battery casing assembly includes a housing 20 and an electrode assembly 10.

[0102] See Figures 8-11 The electrode assembly 10 includes a sleeve 103 and an electrode post 101 located inside the sleeve 103. The sleeve 103 and the electrode post 101 are heat-sealed together by a glass ring 102. The sleeve 103 includes a cylindrical body 1031 and a flanged flange 1032. One end of the cylindrical body 1031 has a flanged flange 1032. The housing 20 includes a first side plate 201. The first side plate 201 is provided with a mounting hole 2011. The cylindrical body 1031 is inserted into the mounting hole 2011. The flanged flange 1032 is welded to the first side plate 201. An annular weld mark 2023 is formed at the connection between the flanged flange 1032 and the first side plate 201.

[0103] In the aforementioned electrode assembly 10, the sleeve 103 and the inner electrode post 101 are sealed together by a glass ring 102, which can effectively ensure the insulation and airtightness between the sleeve 103 and the electrode post 101. During the preparation, glass material can be filled inside the sleeve 103 and the electrode post 101 and melted at high temperature, thereby connecting the sleeve 103 and the electrode post 101 together by hot-melt glass.

[0104] Furthermore, the cylinder 1031 and the flange 1032 in the sleeve 103 are integrally formed structures, which can be prepared by deep drawing and stamping process without welding or splicing, which is more conducive to improving structural strength and consistency.

[0105] In some embodiments, to improve the bonding strength between the glass ring 102 and the electrode post 101, the electrode post 101 and the glass ring 102 are bonded together by a sequentially disposed oxide film layer and a metal transition layer. The oxide film layer is grown on the surface of the electrode post 101, and the metal transition layer is deposited on the surface of the oxide film layer. The metal transition layer is located between the oxide film layer and the glass ring. This structure significantly improves the bonding strength and interfacial stability between the metal electrode post and the glass ring, thereby enhancing the structure's airtightness, thermal cycling stability, and reliability.

[0106] In some specific designs, the oxide film can be an oxide layer of nickel or an oxide layer; the thickness of the oxide film can be 10–200 nm, specifically 50 nm, 100 nm, 150 nm, etc.

[0107] In some specific designs, the metal transition layer is one or more combinations of chromium (Cr) layer, titanium (Ti) layer, molybdenum (Mo) layer, nickel (Ni) layer or nickel-phosphorus alloy (Ni-P alloy) layer; the thickness of the metal transition layer is 50 to 500 nm, specifically 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 400 nm, etc.

[0108] The aforementioned electrode assembly uses glass sealing instead of traditional plastic parts, overcoming the unreliability of existing plastic riveting seals. This avoids the problems of plastic seals aging and leaking under high temperature and high cycle conditions, improving the temperature resistance, airtightness, and long-term cycle reliability of the electrode assembly. It also reduces the likelihood of electrolyte leakage during long-term use and avoids the risk of short circuits caused by plastic aging. The overall structure has excellent airtightness and mechanical strength. The flanged design facilitates welding and fixing of the electrode assembly to the battery casing, making it easier for standardized and modular production applications, improving battery product yield, and thus enhancing battery safety and lifespan. The overall structure is more compact and the dimensions are controllable, which helps meet the application requirements of ultra-thin battery casings.

[0109] The outer shell assembly obtained by welding the aforementioned electrode assembly and the shell has high airtightness, reliability, and safety, as well as a long service life.

[0110] The glass ring 102 mentioned above can be made of low-temperature lead-free glass.

[0111] In some embodiments, the pole post 101 is cylindrical or nearly cylindrical, for example, see [reference needed]. Figure 11 The middle part of pole post 101 is slightly smaller than the two ends. Specifically, the outer diameter of the top and bottom surfaces of pole post 101 is slightly larger than the outer diameter of the middle part.

[0112] In some implementations, see Figure 11 The width L1 of the flange 1032 is 0.2 to 0.5 mm. For example, it can be 0.3 mm, 0.4 mm, etc. The "width of the flange" can be understood as the distance between the outer edge of the flange 1032 and the outer wall of the cylinder 1031.

[0113] Furthermore, the outer diameter D1 of the flange 1032 is 2 to 3 mm, for example, it can be 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, etc.

[0114] In some embodiments, the wall thickness of sleeve 103 is no greater than 0.4 mm, for example, the wall thickness of sleeve 103 is 0.12 mm, 0.15 mm, 0.18 mm, 0.2 mm, etc., and the outer diameter D2 of cylinder 1031 is 1.35 to 2.25 mm, for example, the outer diameter of cylinder 1031 can be 1.5 mm, 2 mm, etc.

[0115] In some embodiments, the height H1 of the glass ring 102 is no greater than 0.5 mm; for example, the height H1 of the glass ring 102 can be 0.475 mm. This is suitable for ultra-thin battery designs. Furthermore, the height of the sleeve 103 is the same as the height of the glass ring 102, and the top surface of the glass ring 102 is flush with the top surface of the sleeve 103, and the bottom surface of the glass ring 102 is flush with the bottom surface of the sleeve 103, to better ensure the integrity of the seal.

[0116] The inner diameter of the glass ring 102 can be 0.5–1.5 mm, and the outer diameter can be 1.2–2.1 mm. For example, the inner diameter of the glass ring 102 can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, etc., and the outer diameter of the glass ring 102 can be 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, etc.

[0117] It is understandable that the "inner diameter of the glass ring" mentioned above refers to the inner diameter at any point between the two end faces of the glass ring (including the end faces), and similarly, the "outer diameter of the glass ring" mentioned above refers to the outer diameter at any point between the two end faces of the glass ring (including the end faces).

[0118] In some implementations, the height H2 of the pole post 101 is not greater than 0.8 mm, for example, it can be 0.725 mm.

[0119] For example, in some specific ways, the components in the electrode assembly 10 may be arranged as follows: the outer diameter of the pole post 101 is 1 mm and the height is 0.725 mm; the height of the glass ring 102 is 0.475 mm; the inner diameter of the cylinder 1031 in the sleeve 103 is 1.8 mm and the thickness is 0.15 mm; the outer diameter of the flange 1032 is 2.6 mm and the width is 0.3 mm.

[0120] In some embodiments, the pole post 101 is made of aluminum, or nickel, or a nickel-based alloy, and the sleeve 103 and the housing 20 are both made of stainless steel, for example, the sleeve 103 and the housing 20 are both made of 316L stainless steel.

[0121] In some solutions, both 102 glass rings and 316L stainless steel can withstand temperatures above 200°C, effectively preventing failures caused by high temperatures.

[0122] In some designs, the glass ring 102 can be made of low-temperature lead-free glass.

[0123] In some embodiments, the axis of the mounting hole 2011 and the pole post 101 of the electrode assembly 10 coincides to ensure alignment. In actual working conditions, the alignment error is no greater than 0.05 mm.

[0124] Furthermore, the thickness of the shell 20 is no more than 0.4 mm.

[0125] In some ways, see Figures 1-3 The shell 20 is square. In this case, the shell 20 can be formed by connecting the first side plate 201 and three other side plates end to end to create a square structure, with the bottom of the square structure sealed by the base plate 202. The shell 20 can be a one-piece molded structure or a split-molded structure.

[0126] The aforementioned battery casing components improve structural strength and sealing airtightness, reduce packaging thickness and assembly error accumulation, effectively improve thermal cycling stress distribution, increase packaging life and reliability, and facilitate automated mass production; they can be applied to high energy density, ultra-thin lithium-ion batteries.

[0127] The aforementioned battery casing assembly can be used in mobile phone batteries, wearable device batteries, and other micro-packaged batteries, exhibiting high versatility in applications.

[0128] All the above-mentioned optional technical solutions can be combined in any way to form optional embodiments of the present invention. That is, any number of embodiments can be combined to meet the needs of different application scenarios. All of these are within the protection scope of this application and will not be described in detail here.

[0129] It should be noted that the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A welding method for a battery casing assembly, characterized in that: include, An electrode assembly and a housing are provided. The electrode assembly includes a sleeve and an electrode post located inside the sleeve. The outer diameters of the top and bottom surfaces of the electrode post are both larger than the outer diameter of the middle part, and the outer diameter of the electrode post gradually and continuously increases from the middle part to the top and bottom surfaces, respectively. The inner wall of the sleeve and the outer wall of the electrode post are fused together by a glass ring. The sleeve includes a cylindrical body, one end of which is formed with a flange, and the cylindrical body and the flange are integrally formed. The housing includes a first side plate, and the first side plate is provided with mounting holes. The electrode assembly and the first side plate are clamped and positioned using welding fixtures, so that the cylinder is inserted into the mounting hole and the flange is fitted with the first side plate. The flange is welded to the first side plate to form an annular weld mark at the connection between the flange and the first side plate.

2. The welding method for the battery casing assembly according to claim 1, characterized in that: When welding the flanged flange to the first side plate, a segmented welding method is used, the segmented welding method including... Multiple welding positions are preset at the connection between the flange and the first side plate. All the welding positions are arranged in a ring. During welding, each welding position is welded sequentially, and there is a preset time interval between the welding times of two adjacent welding positions.

3. The welding method for the battery casing assembly according to claim 2, characterized in that: The total number of welding positions is 4 to 16 segments. The segmented welding method includes numbering all the welding positions sequentially from 1 to N, where N is a natural number greater than 1, welding is performed first at the odd-numbered welding positions, and then welding is performed at the even-numbered welding positions; or, welding is performed first at the even-numbered welding positions, and then welding is performed at the odd-numbered welding positions.

4. The welding method for the battery casing assembly according to claim 1, characterized in that: The area of ​​the first side plate located around the annular weld mark constitutes a non-welded area, which is connected by a heat insulation component and a welding fixture.

5. The welding method for the battery casing assembly according to claim 1, characterized in that: The welding fixture is equipped with a cooling channel. During the welding of the flange to the first side plate, coolant is circulated in the cooling channel. The flow rate of the coolant is 0.2 to 5 L / min, and the temperature of the coolant when it enters the cooling channel is 5 to 40°C.

6. The welding method for the battery casing assembly according to claim 1, characterized in that: When welding the flange to the first side plate, a pulsed laser welding method is used. The laser wavelength used in the pulsed laser welding method is 1000-1100 nm, the pulse width is 0.5-10 ms, the single pulse energy is 0.05-2.0 J, and the spot diameter is 0.1-0.6 mm.

7. The welding method for the battery casing assembly according to claim 1, characterized in that: When welding the flange to the first side plate, a pulse hot-press welding method is used. The welding pressure of the pulse hot-press welding method is 5-50N, the peak heating temperature is 200-450°C, and the heating time is 0.1-2s.

8. A welding fixture, characterized in that: The welding method applied to the battery casing assembly as described in any one of claims 1-7, wherein the welding fixture includes a first clamping member and a second clamping member, the flanged flange and the first side plate are attached to each other and clamped between the first clamping member and the second clamping member, the first clamping member has a first through hole in the middle, and the area on the first side plate for welding with the flanged flange is exposed in the first through hole.

9. The welding fixture according to claim 8, characterized in that: The first clamping member is provided with a slot, and a heat insulation member is provided in the slot. The area of ​​the first side plate located outside the annular weld mark constitutes a non-welded area, and the heat insulation member is in contact with the non-welded area.

10. The welding fixture according to claim 9, characterized in that: The thermal conductivity of the insulation component is less than 10 W / (m·K).

11. The welding fixture according to claim 8, characterized in that: The second clamping member has a cooling channel inside for coolant flow.

12. The welding fixture according to claim 8, characterized in that: The first clamping member and the second clamping member are connected by a guide post. The first clamping member is provided with a first positioning hole, and the second clamping member is provided with a second positioning hole. The guide post passes through the first positioning hole and the second positioning hole in sequence.

13. A battery casing assembly, characterized in that: The battery casing assembly is manufactured using the welding method described in any one of claims 1-7. The battery casing assembly includes a housing and an electrode assembly. The electrode assembly includes a sleeve and an electrode post located inside the sleeve. The sleeve and the electrode post are sealed together by a glass ring. The sleeve includes a cylindrical body, and a flange is formed at one end of the cylindrical body. The housing includes a first side plate, and a mounting hole is provided on the first side plate. The cylindrical body is inserted into the mounting hole. The flange and the first side plate are welded together, and an annular weld mark is formed at the connection between the flange and the first side plate.

14. The battery casing assembly according to claim 13, characterized in that: The width of the flange is 0.2 to 0.5 mm.

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