A bipolar battery structure and its assembly method

Abstract

This invention discloses a bipolar battery structure and its assembly method. The battery structure includes battery plates, electrode groups, a battery casing, and a battery cover. The battery plates consist of bipolar plates with connected positive and negative tabs and unipolar positive and negative plates with tabs rotated 90°. The electrode groups are composed of stacked plates and separators. Individual cells are horizontally connected via bipolar tabs, and the unipolar tabs at both ends are vertically connected to busbars. The top of the battery casing partition wall has a notch for the bipolar tabs to cross; the notch includes a sealing reinforcement groove and a sealing guide groove. The partition wall is thickened and hollowed out at the bottom. The notch is sealed with a comb-shaped sealing clip and adhesive. The assembly method includes electrode group assembly, upright insertion into the casing, notch sealing, and capping. This invention eliminates the need for numerous busbars through direct bipolar tab connection, reducing material costs and internal resistance, and minimizing heat generation. Simultaneously, it improves reliability through optimized sealing structure, making it suitable for various battery types and offering significant economic and technical benefits.

Description

Technical Field

[0001] This invention relates to the field of battery manufacturing technology, specifically to a novel bipolar battery that eliminates most of the busbars inside the battery, reducing battery material costs, and also has shorter cell connection distances, lower internal resistance, lower heat generation during high-current discharge, and better performance. Background Technology

[0002] In traditional chemical battery technology, the electrode groups and tabs inside a single cell are usually electrically connected through a busbar, while the cells are connected in series by bridge welding or through-wall welding. This connection method has the following significant drawbacks: (1) High material consumption: the busbar and bridge connection structure require a large amount of lead, which increases the raw material cost of the battery and the environmental burden. According to statistics, the lead consumption of the connection parts of a conventional 12V lead-acid battery accounts for 10%-15% of the total lead consumption; (2) Limited conductivity: when the current is high, the contact resistance between the busbar and the welding point is prone to local heating, which affects the battery life. Experimental data shows that when the discharge current exceeds 5C, the temperature rise of the connection part can reach 30-50℃, which accelerates the corrosion and aging of lead alloys; High structural complexity: the multi-level connection structure increases the difficulty of the production process, especially the through-wall welding technology, which has extremely high requirements for welding precision. The welding defect rate is usually 0.5%-1%, which leads to an increase in production costs.

[0003] To address the aforementioned issues, this invention proposes a novel bipolar battery structure and assembly technology. This battery eliminates most of the internal busbars, reducing battery material costs. Furthermore, it features shorter cell connection distances, lower internal resistance, lower heat generation during high-current discharge, and better performance. Summary of the Invention

[0004] This invention proposes a novel internal battery structure that eliminates the need for an internal busbar by directly connecting bipolar plates with tabs. By altering the orientation of the unipolar plates at both ends and the position of the internal bipolar tabs, along with tab notches in the battery compartment's internal partition and a sealing agent, reliable sealing of the bipolar battery is achieved. To achieve the above objectives, this invention provides a bipolar battery structure, comprising:

[0005] The battery electrode plate includes a bipolar electrode plate 6 with a positive and negative tab connected together, a unipolar positive electrode plate with the tab rotated 90°, and a unipolar negative electrode plate.

[0006] Electrode group 3 is composed of the battery plates and separators 8 stacked together. The individual cells are horizontally connected by bipolar tabs 9, and the two ends are vertically connected to the busbars 4 and 5 by unipolar tabs.

[0007] Battery slot 1 is divided into several spaces by partition walls. The battery plates are placed in the spaces. The top of the partition wall has a notch 10 for bipolar tabs to cross. The position of the notch 10 corresponds to the position of the bipolar tabs of the electrode group. The notch 10 includes a sealing reinforcement groove 12 and a sealing guide groove 11. The partition wall is thickened and hollowed out from the bottom up. A sealing comb 14 is provided on the notch 10. The bottom of the sealing comb 14 has comb teeth. The bipolar tabs are inserted into the comb teeth of the sealing comb 14 to fix and seal the electrode group 3.

[0008] The battery cover 2 works in conjunction with the battery slot 1 to seal the battery.

[0009] Furthermore, the sealing reinforcement groove 12 of the partition wall notch 10 is a U-shaped or trapezoidal groove with a depth of 2-4mm and a length greater than the width of the notch.

[0010] Furthermore, the tabs of the bipolar electrode plate are widened, and the tab width is determined by standard calculations based on the premise that the temperature rise during maximum current discharge will not cause cracks in the sealing interface. To prevent acid leakage due to acid seepage caused by cracks in the sealing interface due to heat generated during high current discharge, the bipolar tabs are widened, with the tab width calculated based on the premise that the temperature rise during maximum current discharge will not cause cracks in the sealing interface. Since there is no busbar in the bipolar tab area, increasing the tab width has a minimal impact on cost.

[0011] Furthermore, the partition wall is thickened to 10-20mm, and the interior needs to be hollowed out after the partition wall is thickened to reduce weight; the top of the sealing comb 14 has a slot and is connected to the comb teeth.

[0012] The present invention also provides a method for assembling a bipolar battery as described above, characterized by comprising the following steps:

[0013] S1, the battery plates and separators are stacked in layers 8, the individual cells are horizontally connected by bipolar tabs 9, and the two ends are vertically connected by unipolar tabs to form a stacked electrode group 3, and the two ends of the busbars 4 and 5 are welded on the unipolar tabs at both ends.

[0014] S2, the stacked electrode group 3 is placed upright into the groove so that the bipolar tab 9 spans the partition wall gap 10, and the battery plate is inserted into the space between the partition walls.

[0015] S3. Insert the sealing comb card (14) into the bipolar tab from top to bottom along the sealing guide groove (11), and then inject glue sealant into the empty groove in the middle of the sealing comb card (14) in two times. The glue sealant injected for the first time will penetrate into the gaps between the tab and the comb teeth and the gaps between both sides of the sealing comb card (14) and the side walls of the notch, filling these gaps with glue. After waiting for the glue in the gaps to solidify, inject sealant into the empty groove in the middle of the sealing comb card (14) for the second time for sealing.

[0016] S4. Finally, seal the battery cover plate 2 by conventional process to complete the assembly of the bipolar battery.

[0017] Furthermore, the glue sealant can be epoxy resin glue, or molten asphalt seal can be adopted, or molten plastic injection seal can be adopted.

[0018] Furthermore, the battery cover plate 2 can be sealed with glue or by heat sealing. When sealed with glue, the bus bar at the turning point can be directly connected without a cross-bridge part. When heat-sealed, it is necessary to increase the height of the battery cell and adopt through-wall welding.

[0019] Furthermore, for the vertical unipolar tabs on the outer sides of both ends of the electrode group, weld the bus bar and the terminal by conventional process. The welding method is cast welding or soldering. Weld the direct-connected bus bar on the unipolar tab at one end of the turning point and weld the terminal bus bar on the unipolar tab at the other end.

[0020] Furthermore, the internal monomer partition wall of the battery cell is thickened, and the partition wall is hollowed out from the bottom upwards. There is a groove in the middle of the notch of the battery cell partition wall, and sealing guide grooves are provided on both sides of the notch.

[0021] The present invention also provides a battery structure as described above or a battery prepared by the method as described above. The battery is one of a lead-acid battery, a lithium-ion battery, a sodium-ion battery or a potassium-ion battery.

[0022] Advantages of the present invention:

[0023] Reduce material costs: The electrical connection between monomers is achieved through the horizontal direct connection of bipolar tabs, eliminating a large number of bus bars and cross-bridge connection structures inside traditional batteries. Taking a lead-acid battery as an example, the consumption of lead materials at the connection parts can be reduced by 60%-70%, significantly reducing the raw material cost and environmental burden.

[0024] Optimize electrical conductivity: The current transmission distance between monomers is shortened, and the bipolar tabs are designed with widened width, reducing the internal resistance of the battery. When discharging at a large current, the local heating caused by contact resistance is reduced, slowing down the corrosion and aging of the electrode material, and improving the battery life.

[0025] Simplified production process: The connection method of the busbars at both ends is simple, which reduces the reliance on high-precision welding, reduces the difficulty of the production process and the welding defect rate, and improves production efficiency.

[0026] Improved sealing reliability: The battery compartment partition wall gap is equipped with a sealing reinforcement groove, a sealing guide groove, and a sealing comb. Through the multi-seal structure design, combined with sealing materials such as epoxy resin, the sealing effect at the bipolar tabs passing through the partition wall is ensured, reducing the risk of electrolyte leakage.

[0027] The structure is reasonably designed: the partition wall is thickened to 10-20mm to ensure reliable sealing, and the bottom is hollowed out to reduce weight and enhance heat dissipation; the sealing comb not only fixes the pole group, but also strengthens the seal, and the overall structure takes into account both functionality and economy. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 It has a bipolar battery structure;

[0030] Figure 2 It is a bipolar battery electrode group;

[0031] Figure 3 The shape of the plates in a bipolar battery;

[0032] Figure 4 This is a stacking method for bipolar battery electrode groups;

[0033] Figure 5 It is a bipolar battery compartment;

[0034] Figure 6 This is a cross-sectional view of a bipolar battery compartment.

[0035] Figure 7 This is a cross-sectional view of a bipolar battery.

[0036] Figure 8 For sealing the gaps in the partition wall of bipolar batteries;

[0037] Figure 9 Schematic diagram of sealing the gap in the partition wall of a bipolar battery Figure 1 ;

[0038] Figure 10 Schematic diagram of sealing the gap in the partition wall of a bipolar battery Figure 2 ;

[0039] Figure 11 For the sealing effect of the gap in the partition wall of the bipolar battery Figure 3 ;

[0040] Figure 12 A schematic diagram of the bipolar tab portion of the polar group after injection molding;

[0041] in:

[0042] 1-Battery slot; 2-Battery cover; 3-Pole group; 4-End direct connection busbar; 5-Terminal busbar; 6-Bipolar plate; 7-Unipolar plate; 8-Separator; 9-Bipolar tab; 10-Separator notch; 11-Sealing guide groove; 12-Sealing reinforcement groove; 13-Hollow structure; 14-Sealing comb. Detailed Implementation

[0043] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0044] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of a descriptive feature, integral, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or sets.

[0045] To keep the drawings concise, only the parts relevant to the invention are shown schematically in each figure, and they do not represent the actual structure of the product. Furthermore, for ease of understanding, in some figures, only one of components with the same structure or function is shown schematically, or only one is labeled. In this document, "one" can mean not only "only one" but also "more than one".

[0046] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0047] In the embodiments shown in the accompanying drawings, the directional indications (such as up, down, left, right, front, and back) used to explain the structure and movement of the various components of the invention are relative rather than absolute. These descriptions are appropriate when these components are in the positions shown in the drawings. If the descriptions of the positions of these components change, these directional indications also change accordingly.

[0048] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0050] This embodiment aims to provide a detailed description of a bipolar battery structure and its assembly method, with each step and component specifically explained in conjunction with the accompanying drawings.

[0051] Electrode preparation and electrode group assembly

[0052] Electrode design and fabrication: according to Figure 3 The electrode shapes shown are used to prepare three types of battery electrode plates. Among them, the positive and negative electrodes of the bipolar electrode plate 6 with side tabs are integrally connected by side tabs, and the thickness of the tabs is consistent. The thickness of the positive and negative electrodes can be adjusted according to the requirements. The unipolar electrode plate 7 includes a unipolar positive electrode plate and a unipolar negative electrode plate, and the tabs of the unipolar electrode plate are rotated 90° relative to the electrode plate body, and the ends of the tabs are upright.

[0053] Extreme group stacking: reference Figure 4 The stacking method shown involves alternating layers of bipolar plates 6, unipolar positive plates, unipolar negative plates, and separators 8. During the stacking process, it is ensured that the interior of each cell is directly connected in the horizontal direction through the tabs 9 of the bipolar plates, while the tabs of the unipolar plates at both ends stand upright.

[0054] Busbar welding: Using a casting welding process, a terminal busbar 4 is welded to the upright unipolar tab at one end of the electrode group 3, and a terminal busbar 5 is welded to the upright unipolar tab at the other end, forming a busbar as shown in the image. Figure 2 The complete pole group 3 is shown.

[0055] Battery slot preparation

[0056] according to Figure 5 and Figure 6 The structure shown is used to fabricate battery compartment 1:

[0057] The partition wall between individual cells inside the battery compartment is thickened to 18mm, and a notch 10 is opened at the top of the partition wall corresponding to the position of the bipolar tab 9 of the electrode group.

[0058] A U-shaped sealing reinforcement groove 12 with a depth of 3mm is set in the middle of the partition wall gap 10, and its length is slightly larger than the width of the gap; sealing guide grooves 11 are set on both sides of the gap to assist in the installation of the sealing components. When the sealing comb (14) is inserted into the gap and sealant (such as epoxy resin glue) is injected, the glue will fill the U-shaped groove to form a "maze-like" sealing interface, which greatly extends the possible penetration path of the electrolyte, thereby significantly reducing the risk of electrolyte leakage. The U-shaped groove can increase the contact area between the sealant and the partition wall gap, and the groove structure improves the connection between the sealant and the partition wall through mechanical interlocking, avoiding the peeling of the sealing layer from the partition wall due to battery vibration, temperature changes, etc., and ensuring the sealing stability during long-term use. For materials such as asphalt and injection-molded sealant, the U-shaped groove can compensate for the dimensional deviation during the processing of parts by accommodating more sealing material, ensuring the uniform thickness of the sealing layer and avoiding local weak points in the sealing. The sealing guide grooves 11 are set along both sides of the partition wall gap, and their shape matches the two sides of the sealing comb 14. During assembly, the guide groove guides the insertion of the sealing comb 14, ensuring that the comb teeth are precisely engaged between the bipolar tabs 9, avoiding damage to the tabs or misalignment of the seal due to installation misalignment. When applying sealant, the guide groove temporarily stores the sealant. During the insertion of the sealing comb, the sealant evenly fills the gap between the comb and the notch sidewall along the guide groove, ensuring that there are no air bubbles or voids in the gap, forming a continuous and complete sealing layer. The combined design of the U-shaped sealing reinforcement groove 12 and the sealing guide groove 11 improves the reliability of the bipolar battery from two dimensions: "precise assembly" and "long-lasting sealing".

[0059] The partition wall is perforated from the bottom upwards to form a perforated structure 13, which reduces weight and enhances heat dissipation.

[0060] Extreme group entry slot

[0061] The electrode group 3, with the busbar welded, is placed upright into the tank as a whole, ensuring that the bipolar tabs 9 of electrode group 3 span the gap 10 in the battery tank partition wall, with the bottom of the tabs flush with the gap surface. The battery plates are then inserted into the space between the partition walls. The state after placement can be referenced. Figure 7 The diagram shows a cross-sectional view of a bipolar battery.

[0062] Seal of gaps in partition walls

[0063] The gap 10 in the partition wall was sealed using adhesive, and the specific operation is as follows:

[0064] according to Figure 8 The structure shown is a pre-sealed comb card 14, which has a comb tooth section at the bottom and a slot at the top that communicates with the comb tooth section.

[0065] Apply epoxy resin glue to the sealing guide grooves 11 on both sides of the partition wall gap 10. Insert the sealing comb card 14 into the bipolar tab from top to bottom along the sealing guide groove 11, and then inject glue into the empty groove in the middle of the sealing comb card 14 in two steps. The glue injected for the first time will penetrate into the gaps between the tab and the comb teeth and the gaps between both sides of the sealing comb card 14 and the side walls of the gap, filling these gaps with glue. After waiting for the glue in the gaps to solidify, inject glue into the empty groove in the middle of the sealing comb card 14 for the second time for sealing.

[0066] As Figure 9 and Figure 10 shown, insert the sealing comb card 14 into the bipolar tab 9 from top to bottom along the sealing guide groove 11, ensuring that the gaps between the tab and the comb teeth and the gaps between both sides of the comb card and the side walls of the gap are filled with glue.

[0067] After the first layer of glue solidifies, inject glue into the empty groove at the top of the sealing comb card 14 to complete the complete sealing, and the sealing effect is as Figure 11 shown.

[0068] If injection molding sealing is adopted, after the pole group completes the casting welding of the two ends of the tabs, perform injection molding on the bipolar tab 9 part inside the monomer to form an injection molded part with a similar sealing comb card structure, as Figure 12 shown, then insert the entire pole group into the slot, and then use glue to seal the injection molded part and the battery slot partition wall gap 10.

[0069] Cover

[0070] Adopt glue sealing to cover. Align the battery cover plate 2 with the battery slot 1, and apply sealing glue to the joint surface. Due to the adoption of glue sealing, the bus bar at the turning point adopts a direct connection method and no bridging parts are required. The structure of the bipolar battery after covering is as Figure 1 shown. If thermal sealing is adopted, the battery slot 1 needs to be heightened and the through-wall welding process is used for sealing.

[0071] Through the above embodiments, the assembly of the bipolar battery can be completed. This assembly process is simple, the sealing is reliable, and it can effectively improve the battery performance.

[0072] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: still can modify the specific implementation manners of the present invention or make equivalent replacements, and any modification or equivalent replacement without departing from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for assembling a bipolar battery, characterized in that, Includes the following steps: S1, the battery plates and separators (8) are stacked together, and the individual cells are horizontally connected by bipolar tabs (9), and the two ends are vertically connected by unipolar tabs to form a stacked electrode group (3). Busbars (4,5) are welded on the two ends of the unipolar tabs. S2, the stacked electrode group (3) is upright in the battery compartment (1). The battery compartment (1) is divided into several spaces by partition walls. The battery plates are placed in the spaces. The top of the partition wall is provided with a partition wall notch (10) for bipolar tabs to cross. The partition wall notch (10) includes a sealing reinforcement groove (12) and a sealing guide groove (11) so that the bipolar tabs (9) cross the partition wall notch (10) and the battery plates are inserted into the spaces separated by the partition walls. S3, insert the sealing comb card (14) into the bipolar tab from top to bottom along the sealing guide groove (11), and then inject glue sealant into the empty groove in the middle of the sealing comb card (14) twice. The first injection of glue will penetrate into the gap between the tab and the comb teeth and the gap between the two sides of the sealing comb card (14) and the side wall of the notch, so that these gaps are filled with glue. After the glue in the gaps solidifies, inject glue sealant into the empty groove in the middle of the sealing comb card (14) a second time. S4. Finally, seal the battery cover (2) according to the conventional process to complete the assembly of the bipolar battery.

2. The method according to claim 1, characterized in that, The adhesive sealant is epoxy resin, molten asphalt, or molten plastic.

3. The method according to claim 1, characterized in that, The battery cover (2) is sealed with glue or heat-sealed. When glue is used, the busbar at the bend is directly connected and no cross-bridge parts are needed. When heat-sealed, the battery compartment needs to be heightened and wall-welded.

4. The method according to claim 1, characterized in that, For the vertical unipolar tabs on both sides of the pole group, the busbars and terminals are welded using conventional processes. The welding method is casting welding or sintering welding. A direct busbar is welded to the unipolar tab at one end of the bend, and a terminal busbar is welded to the unipolar tab at the other end.

5. The assembly method according to claim 1, characterized in that, The internal partition walls of the battery compartment are thickened and hollowed out from the bottom up. There is a groove in the middle of the gap in the battery compartment partition wall and sealing guide grooves on both sides of the gap.

6. A bipolar battery structure assembled by any one of the assembly methods described in claims 1-5, characterized in that, include: The battery electrode plate includes a bipolar electrode plate (6), a unipolar positive electrode plate with tabs rotated 90° and a unipolar negative electrode plate, wherein the positive and negative electrodes of the bipolar electrode plate are integrally connected by bipolar tabs. The electrode group (3) is composed of the battery plates and separators (8) stacked together. The individual cells are horizontally connected by bipolar tabs (9), and the two ends are vertically connected to the busbars (4,5) by unipolar tabs. Battery slot (1), the battery slot (1) is divided into several spaces by partition walls, the battery plates are placed in the spaces, the top of the partition wall is provided with a partition wall notch (10) for bipolar tabs to cross, the position of the partition wall notch (10) corresponds to the position of the bipolar tabs of the electrode group, the partition wall notch (10) includes a sealing reinforcement groove (12) and a sealing guide groove (11), the partition wall is thickened and the partition wall is hollowed out from bottom to top, a sealing comb (14) is provided on the partition wall notch (10), the bottom of the sealing comb (14) is provided with comb teeth, the bipolar tabs are inserted into the comb teeth of the sealing comb (14) to complete the fixing and sealing of the electrode group (3); The battery cover (2) works in conjunction with the battery slot (1) to seal the battery.

7. The bipolar battery structure according to claim 6, characterized in that, The sealing reinforcement groove (12) of the partition wall gap (10) is a U-shaped or trapezoidal groove with a depth of 2-4mm and a length greater than the gap width.

8. The bipolar battery structure according to claim 6, characterized in that, The tabs of the bipolar plate are widened, and the tab width is determined by standard calculation based on the principle that the temperature rise during maximum current discharge will not cause cracks in the sealing interface.

9. The bipolar battery structure according to claim 6, characterized in that, The partition wall is thickened to 10-20mm. After the partition wall is thickened, the interior needs to be hollowed out to reduce the weight. The top of the sealing comb card (14) has a slot and is connected to the comb teeth.

10. A battery prepared by the method according to any one of claims 1-5, or a bipolar battery structure according to any one of claims 6-9, characterized in that... The battery is one of the following: lead-acid battery, lithium-ion battery, sodium-ion battery, or potassium-ion battery.

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