Battery pack and battery thereof

Abstract

The utility model relates to new energy battery technical field discloses a battery pack and its battery, its battery includes: the electric core body, has first end and second end along the first direction, the tab portion, it extends from the both ends of the electric core body along the first direction, the tab portion at the first end is called first tab portion, the size of first tab portion in the first direction is a mm, the tab portion at the second end is called second tab portion, the size of second tab portion in the first direction is b mm, satisfy: a > b. The utility model discloses such structure, can reduce the occupation to space, improve the space utilization of battery shell inside, and further improve the energy density of battery.

Description

Technical Field

[0001] This utility model relates to the field of new energy battery technology, and in particular to a battery pack and its battery. Background Technology

[0002] During the battery manufacturing process, the tabs of the battery cell need to be welded to the terminals, and then the tabs are bent. The tabs occupy too much space inside the battery casing, resulting in low space utilization inside the battery casing and low energy density of the battery. Utility Model Content

[0003] The purpose of this invention is to provide a battery pack and its battery that can improve the energy density of the battery.

[0004] To achieve the above objectives, one aspect of the present invention provides a battery, comprising:

[0005] The battery cell body has a first end and a second end along a first direction;

[0006] The electrode portion extends from both ends of the battery cell body along the first direction. The electrode portion located at the first end is referred to as the first electrode portion, and the size of the first electrode portion in the first direction is a mm. The electrode portion located at the second end is referred to as the second electrode portion, and the size of the second electrode portion in the first direction is b mm, satisfying: a > b.

[0007] Another aspect of this utility model provides a battery pack including the aforementioned batteries and a busbar, wherein the busbar is electrically connected to the terminals of at least two of the batteries.

[0008] This utility model provides a battery pack and its battery, which have the following advantages compared with the prior art:

[0009] The battery of this invention includes a cell body and tabs. The tabs include a first tab and a second tab disposed at both ends of the cell body. The dimension of the first tab along the extension direction is larger than that of the second tab along the extension direction. When welding the tabs, the second tab is first welded to the terminal post, then the cell body is placed into the casing, and then the first tab is welded. The larger dimension of the first tab along the extension direction compared to the second tab facilitates the welding operation and also facilitates subsequent cutting of the first tab, reducing space occupation. Furthermore, the smaller size of the first tab improves the space utilization rate inside the battery casing, thereby increasing the energy density of the battery.

[0010] The battery pack of this utility model includes the battery described above, which reduces the space occupied, improves the space utilization rate inside the battery casing, and thus improves the energy density of the battery. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the electrode tabs of the battery cell in the embodiment of this utility model in the unfolded state.

[0012] Figure 2 yes Figure 1 Enlarged diagram of point A in the middle.

[0013] Figure 3 yes Figure 1 Enlarged diagram of point B in the middle.

[0014] Figure 4 This is a schematic diagram of the electrode tab bending state of the battery cell according to an embodiment of this utility model.

[0015] Figure 5 yes Figure 4 Enlarged diagram of point C in the middle.

[0016] Figure 6 This is a schematic diagram of the battery of this utility model.

[0017] In the diagram, 1. Battery cell body; 2. Terminal tab; 3. Housing; 4. Cover plate; 5. Terminal post; 21. First terminal tab; 22. Second terminal tab;

[0018] X, the first direction. Detailed Implementation

[0019] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0020] In the description of this utility model, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They 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 this utility model. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 utility model based on the specific circumstances.

[0022] Furthermore, in the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0023] Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0024] A battery according to an embodiment of the present invention includes: a cell body 1 and a tab portion 2, wherein the cell body 1 has a first end and a second end along a first direction X.

[0025] The battery cell body 1 includes a separator and two types of electrodes with opposite polarities, namely a positive electrode and a negative electrode. The battery cell operates by the movement of metal ions between the positive and negative electrodes. The cycle process of the battery cell is the process of metal ions moving from the positive electrode to the negative electrode and then from the negative electrode to the positive electrode.

[0026] As an insulating layer, the separator prevents short circuits inside the battery cell caused by contact between the positive and negative electrodes. As a semi-permeable layer, the separator prevents larger molecules from passing through while allowing smaller charged ions to pass through.

[0027] Please refer to Figures 1-3 The tab 2 extends from both ends of the cell body 1 along the first direction. The tab 2 located at the first end of the cell body 1 along the first direction X is denoted as the first tab 21, and the size of the first tab 21 in the first direction X is a mm. The tab 2 located at the second end of the cell body 1 along the first direction X is denoted as the second tab 22, and the size of the second tab 22 in the first direction X is b mm, satisfying: a > b.

[0028] The battery includes a cell, which comprises a cell body 1 and tabs 2. Tabs 2 are electrically connected to electrode plates. The tabs provide either a positive or negative electrode for inputting or outputting to the cell body 1. The tabs connect to terminals to achieve electrical connection between the cell body 1 and the terminals. Specifically, the positive tab is electrically connected to the positive electrode plate, and the negative tab is electrically connected to the negative electrode plate. The cell body 1 is charged and discharged through the positive and negative tabs. It should be noted that the tabs of the cell are formed by stacking and connecting regions of the positive electrode plate that are not coated with a positive active material layer, or by stacking and connecting regions of the negative electrode plate that are not coated with a negative active material layer. If the tab is used to output the positive electrode of the cell, it is a component formed by stacking and connecting regions of the positive electrode plate that are not coated with a positive active material layer; if the tab is used to output the negative electrode of the cell, it is a component formed by stacking and connecting regions of the negative electrode plate that are not coated with a negative active material layer. The electrode plate includes a current collector and an active material layer, with the active material layer coated on the surface of the current collector. If the electrode is a positive electrode, the current collector can be made of aluminum, and the active material layer can be made of lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. If the electrode is a negative electrode, the current collector can be made of copper, and the active material layer can be made of carbon or silicon, etc.

[0029] In this embodiment, the tab 2 is a collection of tabs on each cell body 1.

[0030] The first electrode tab 21 can be either a positive electrode tab or a negative electrode tab. Similarly, the second electrode tab 22 can be set to have opposite polarities.

[0031] Please refer to Figure 6 The battery also includes a casing 3 and a cover plate 4. The casing 3 has an opening, and the cover plate 4 is disposed at the opening. The cover plate 4 and the casing 3 form a receiving space. The cell body 1 and the electrode tab 2 are at least partially disposed in the receiving space.

[0032] Specifically, the housing 3 has a first hole and a second hole at both ends, and both the first hole and the second hole are connected to the interior of the housing 3. The cover plate 4 is installed on the first hole and the second hole respectively and is referred to as the first cover plate assembly and the second cover plate assembly respectively. Both the first cover plate assembly and the second cover plate assembly include a pole post, which is used to electrically connect with the electrode ear 2.

[0033] When welding the tab 2, the second tab 22 is first welded to the pole of the second cover plate assembly, then the cell body 1 is placed into the housing, and then the first tab 21 and the pole of the first cover plate assembly are welded.

[0034] The second electrode ear 21 is smaller than the first electrode ear 22. The welding of the second electrode ear 21 to the pole post of the second cover plate assembly is performed before assembly with the housing 3. When welding the second electrode ear 22 to the pole post of the second cover plate assembly using welding equipment, the process dimensions required by the welding equipment can be met within the range of the second electrode ear 22. The size of the second electrode ear 21 does not need to be too large to meet the welding operation requirements, thereby reducing the space occupied by the second electrode ear 21 in the housing 3 after entering the housing 3.

[0035] Since the first tab 21 is welded after the cell body 1 is placed into the housing 3, the dimension of the first tab 21 along the extension direction is set to be larger than the dimension of the second tab 22 along the extension direction. When welding the first tab 21 and the pole of the first cover plate assembly, the tab installed in the housing 3 can be placed on the pole, and more welding process space is provided for the welding equipment, which is convenient for welding operations, meets the requirements of welding operations, avoids false welding, and ensures welding quality. In turn, it ensures the overcurrent capacity between the tab and the pole. For the battery during high-rate fast charging, it reduces the safety risks such as large heat generation of the tab, excessive internal resistance of the battery, and battery thermal control, and ensures the overall charging and discharging rate of the battery. At the same time, it facilitates the subsequent cutting operation of the first tab 21, reduces the size of the first tab 21 to reduce the space occupation, thereby improving the space utilization rate inside the battery housing 3 and thus improving the energy density of the battery.

[0036] The dimensions a mm of the first tab 21 in the first direction X and the dimensions b mm of the second tab 22 in the first direction X are both dimensions of the tab 2 stretched flat along a plane parallel to the large surface of the cell body 1.

[0037] When measuring a and b, common length measuring tools such as rulers and tape measures can be used.

[0038] When measuring a, take the battery cell with the tab 2 in the unfolded state, take the first end of the battery cell body 1 in the first direction X as the reference edge, and measure the reference edge and the edge of the end of the first tab 21 away from the reference edge along the first direction X using a length measuring tool. Measure multiple times and take the average value to obtain the dimension a mm of the first tab 21 in the first direction X.

[0039] When measuring b, take the battery cell with the tab 2 in the unfolded state, take the second end of the battery cell body 1 in the first direction X as the reference edge, and use a length measuring tool to measure the reference edge and the edge of the second tab 22 away from the reference edge along the first direction X. Measure multiple times and take the average value to obtain the dimension b mm of the second tab 22 in the first direction X.

[0040] In some embodiments, the electrode portion 2 includes a plurality of electrode tabs, each electrode tab being stacked, each electrode tab extending from a first end or a second end along a first direction X, and the edges of each electrode tab along the first direction X being flush in the stacking direction.

[0041] The electrode portion 2 can be either the first electrode portion 21 or the second electrode portion 22.

[0042] After the first tab 21 and the second tab 22 are welded to the terminal post, the welded first tab 21 and the second tab 22 are trimmed to make the end edges of the first tab 21 and the second tab 22 flush, that is, the edges of each tab in the first direction X are flush in the stacking direction. After the tab 2 is welded to the terminal post, the tab 2 can be trimmed to make the end edges of the tab 2 flush. This prevents the tab 2 from overlapping with the housing 3, avoids the risk of insulation failure, prevents battery short circuits, and reduces the space occupied by the tab 2 inside the housing 3, thereby improving the space utilization rate inside the battery housing 3 and thus improving the energy density of the battery.

[0043] In some embodiments, please refer to Figures 4-5 The dimensions a mm of the first electrode ear 21 in the first direction X and the dimensions b mm of the second electrode ear 22 in the first direction X also satisfy: 1 ​​≤ a – b ≤ 20. Preferably, ab can take values ​​of 1, 3, 9, 15, 17, 20, etc.

[0044] If ab is too small, insufficient welding space will easily occur when welding the first tab 21 to the terminal post of the first cover plate assembly. This can easily lead to incomplete welds, affecting welding quality and consequently the current-carrying capacity between the first tab 21 and the terminal post. During high-rate fast charging, the tabs generate significant heat, resulting in excessive internal resistance and potential safety risks such as thermal control issues. It also affects the overall charge / discharge rate of the battery. If ab is too large, the tab 2 is prone to overlapping with the casing 3, causing insulation failure and short circuits. Furthermore, cutting the tab 2 results in excessively long material being cut off, leading to material waste and high battery costs. By adjusting the dimensions a mm of the first tab 21 in the first direction X and b mm of the second tab 22 in the first direction X to meet the above-mentioned range, the welding quality requirements can be met without the dimensional difference being too small, while avoiding insulation failure and material waste caused by an excessive dimensional difference.

[0045] In some embodiments, both the first electrode ear 21 and the second electrode ear 22 are multi-electrode structures. The dimensions a mm of the first electrode ear 21 and b mm of the second electrode ear 22 in the first direction X also satisfy: 1 ​​≤ a – b ≤ 18. Preferably, a – b can take values ​​such as 1, 2, 4, 6, 11, 13, 18, etc.

[0046] Since the first tab 21 and the second tab 22 are multi-tab structures, the multi-tab structure is easier to bend, which facilitates the battery manufacturing process. When the tab 2 is welded to the terminal post, the welding quality can be guaranteed even when the welding space is small. When the above range is met, the welding operation needs can be met because the size difference is not too small, and the electrode material will not be wasted because the size difference is too large. While ensuring the welding quality, insulation failure is further prevented.

[0047] In some embodiments, the tab portion 2 is formed by stacking multiple tab sheets, with w layers and h1 mm thickness for each layer. The distance between the midpoint of the tab portion 2 in the stacking direction and the bending position of the tab portion 2 in the stacking direction is c mm, satisfying: 0.005 ≤ (w*h1) / c ≤ 22. Preferably, (w*h1) / c can take values ​​such as 0.005, 0.01, 0.9, 3, 10, 13, 19, 22, etc.

[0048] In addition to controlling the size of ab within the range of 1mm–20mm, the thickness h1 mm of the tab and the distance c mm between the midpoint of the tab 2 in the stacking direction and the bending position of the tab 2 in the stacking direction simultaneously affect the welding quality and insulation effect of the tab 2. Therefore, while meeting the welding quality requirements, the insulation effect of the battery can be guaranteed by controlling and adjusting h1 and c, avoiding the tab 2 from overlapping with the casing 3, which could lead to insulation failure and cause battery short circuits.

[0049] If the value of (w*h1) / c is too large, the space for the tab 2 between the cell body 1 and the cover assembly will be small, leading to redundancy in the tab 2. This can cause the tab 2 to overlap with the shell 3, increasing the risk of insulation failure and short circuit. The tab 2 is also prone to misalignment, which can affect the welding quality between the tab 2 and the terminal post. Furthermore, the edge of the tab 2 before cutting will be uneven, requiring more material to be cut off. Cutting off too much material from the tab 2 will affect heat dissipation and introduce more lint, increasing manufacturing costs. If the value of (w*h1) / c is too small, the current-carrying cross-section of the tab 2 will be reduced, the resistance of the tab 2 will increase, the temperature of the structural components will rise more, affecting the current-carrying capacity. In addition, more material from the tab 2 will need to be cut off, increasing manufacturing costs.

[0050] The number of tab layers, w, also satisfies: 20 ≤ w ≤ 150. Preferably, w can take values ​​of 20, 30, 45, 62, 77, 89, 105, 135, 144, 150, etc.

[0051] If the value of w is too large, misalignment is likely to occur in the tab 2, affecting the welding quality between the tab 2 and the terminal post. The unevenness of the edge of the tab 2 before cutting will be more serious, and more of the tab 2 needs to be cut off. If the value of w is too small, less active material will be coated on the cell body 1, resulting in a low energy density of the battery.

[0052] The thickness h1 mm of each tab layer also satisfies: 0.002 ≤ h1 ≤ 0.03. Preferably, h1 can take values ​​such as 0.002, 0.008, 0.01, 0.015, 0.018, 0.021, 0.026, 0.03, etc.

[0053] If h1 is too large, misalignment is likely to occur in the tab 2, resulting in significant unevenness at the edge of the tab 2 before cutting. This requires cutting off more of the tab 2 and increases its space usage, leading to low battery space utilization. If h1 is too small, the current-carrying cross-section of the tab 2 decreases, increasing its resistance and affecting its current-carrying capacity. Furthermore, if the tab is too thin, the tab 2 is prone to folding and tearing, affecting the welding quality between the terminal and the tab 2.

[0054] The distance c mm between the midpoint of the tab 2 in the stacking direction and the bending position of the tab 2 in the stacking direction also satisfies: 0.2 ≤ c ≤ 10. Preferably, c can take values ​​such as 0.2, 0.6, 1, 4, 6, 9, 10, etc.

[0055] If the value of c is too large, the space occupied by the tab 2 will be too large, resulting in low space utilization of the battery and more of the tab 2 that needs to be cut off, increasing manufacturing costs. If the value of c is too small, the length of the tab 2 that can be gathered will be small, and the tab 2 will easily overlap with the cover plate, causing a short circuit.

[0056] When measuring c, common length measuring tools such as rulers and tape measures can be used.

[0057] When measuring c, take the battery cell with the tab 2 bent. Take the plane where the midpoint of the battery cell body 1 is located in the stacking direction as the reference plane. This reference plane is parallel to the large surface of the battery cell. Measure the distance between the reference plane and the bent position of the tab 2 along the stacking direction using a length measuring tool. Take multiple measurements and take the average value to obtain the distance c mm between the midpoint of the tab 2 in the stacking direction and the bent position of the tab 2 in the stacking direction.

[0058] In this embodiment, the first electrode ear 21 is the positive electrode ear, and the second electrode ear 22 is the negative electrode ear.

[0059] When welding the tab 2, the negative tab is first welded to the terminal post, then the cell body 1 is placed into the housing, and then the positive tab is welded. This facilitates the assembly of the cell and the housing 3, improves assembly efficiency, reduces the impact of the assembly process on the tab 2, prevents the tab 2 from folding, and ensures the current carrying capacity of the tab 2.

[0060] The dimension a mm of the first pole ear 21 in the first direction X also satisfies: 20 ≤ a ≤ 60. Preferably, a can take values ​​such as 20, 26, 34, 38, 41, 47, 56, 60, etc.

[0061] When the above range is met, the first electrode ear 21 will not have too many cutting parts due to excessive size, thus reducing manufacturing costs, nor will it be difficult to perform welding operations due to excessive size, thus ensuring that the first electrode ear 21 can be successfully welded onto the electrode post.

[0062] This embodiment also provides a battery pack, including the aforementioned batteries and a busbar, with multiple batteries arranged in sequence, and the busbar electrically connected to the terminals of at least two batteries.

[0063] Specifically, the individual batteries are connected together via a busbar, which collects the current from each battery and outputs the current from the battery pack.

[0064] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A battery, characterized by, include: The battery cell body has a first end and a second end along a first direction; The electrode portion extends from both ends of the battery cell body along the first direction. The electrode portion located at the first end is referred to as the first electrode portion, and the size of the first electrode portion in the first direction is a mm. The electrode portion located at the second end is referred to as the second electrode portion, and the size of the second electrode portion in the first direction is b mm, satisfying: a > b.

2. The battery according to claim 1, characterized in that: The electrode portion includes a plurality of electrode tabs, which are stacked together. Each electrode tab extends from the first end or the second end along the first direction, and the edges of each electrode tab in the first direction are flush in the stacking direction.

3. The battery according to claim 1, characterized in that: The dimensions a mm of the first electrode ear in the first direction and the dimensions b mm of the second electrode ear in the first direction also satisfy: 1 ​​≤ a – b ≤ 20.

4. The battery according to claim 3, characterized in that: Both the first electrode ear and the second electrode ear are multi-electrode structures; The dimensions a mm of the first electrode ear in the first direction and the dimensions b mm of the second electrode ear in the first direction also satisfy: 1 ​​≤ a – b ≤ 18.

5. The battery according to claim 1, characterized in that: The electrode tab is formed by stacking multiple electrode tabs, the number of electrode tabs is w, the thickness of each electrode tab is h1 mm, and the distance between the midpoint of the electrode tab in the stacking direction and the bending position of the electrode tab in the stacking direction is c mm, satisfying: 0.005≤(w*h1) / c≤22.

6. The battery according to claim 5, characterized in that: The number of layers w of the tabs also satisfies: 20≤w≤150.

7. The battery according to claim 5, characterized in that: The thickness h1 mm of each of the tabs also satisfies: 0.002≤h1≤0.

03.

8. The battery according to claim 5, characterized in that: The distance cmm between the midpoint of the tab in the stacking direction and the bending position of the tab in the stacking direction also satisfies: 0.2≤c≤10.

9. The battery according to claim 1, characterized in that: The first electrode tab is the positive electrode tab, and the second electrode tab is the negative electrode tab; The dimension a mm of the first electrode ear in the first direction also satisfies: 20 ≤ a ≤ 60.

10. A battery, characterized by include: A shell having an opening; A cover plate is provided over the opening, and the cover plate and the housing form a receiving space, wherein the battery cell body and the electrode tab are at least partially disposed within the receiving space.

11. A battery pack, characterized in that, include: The battery as described in any one of claims 1-10 has terminals; A bus that is electrically connected to the terminals of at least two of the batteries.

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