Battery cell and battery pack

Abstract

The utility model discloses a single battery and a battery pack, and belongs to the technical field of batteries, the single battery comprises: a shell assembly having an accommodating cavity; the roll core is arranged in the containing cavity, and the roll core is provided with a main body part and arc parts located on the two sides of the main body part; the connecting piece is arranged in the accommodating cavity; and the sensing element is arranged in the accommodating cavity, and the sensing element is arranged on the arc part through a connecting piece so as to measure the pressure or the pressure change of the roll core on the arc part. The sensing element is arranged on the arc part of the roll core through the connecting piece, the roll core usually deteriorates preferentially at the position of the arc part in the cycle use process of the battery, and the sensing element is arranged at the position, so that the pressure or the pressure change can be detected earlier than at other positions, and the expansion of the roll core can be sensed in time.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and in particular relates to a battery cell and a battery pack. Background Art

[0002] In a square lithium-ion battery, as the core cycle progresses, gas is generated inside the core and it expands. In order to understand the expansion of the core, an early warning of the expansion degree is required, but current batteries cannot sense the expansion of the core in time. Utility Model Content

[0003] Purpose of the present application: An embodiment of the present application provides a battery cell, aiming to overcome the technical problem of not being able to sense the expansion of the winding core in a timely manner; another purpose of an embodiment of the present application is to provide a battery pack.

[0004] Technical solution: A battery cell according to an embodiment of the present application includes:

[0005] A shell assembly having a receiving cavity;

[0006] A winding core is arranged in the accommodating cavity, and the winding core has a main body and arc parts located on both sides of the main body;

[0007] A connecting piece, arranged in the accommodating cavity;

[0008] A sensing element is disposed in the accommodating cavity. The sensing element is disposed on the arc portion through the connecting member to measure the pressure or pressure change of the winding core on the arc portion.

[0009] In some embodiments, the connecting member is configured as an insulating member covering the sensing element and the outer periphery of the winding core.

[0010] In some embodiments, the connecting member and the diaphragm of the winding core are an integrated structure, and the connecting member covers the sensing element to fix the sensing element on the winding core.

[0011] In some embodiments, the battery cell comprises:

[0012] A fixing member, disposed in the accommodating cavity, through which the connecting member is connected to the winding core;

[0013] The connecting member is coated on the sensing element, and is disposed between the sensing element and the shell component to separate the sensing element and the shell component, and the connecting member and the shell component are separated from each other.

[0014] In some embodiments, along the width direction of the shell component, the maximum dimension of the shell component is H;

[0015] The connecting member fixes the sensing element to one side of the arc portion in the width direction, and a minimum distance between the connecting member and the shell component in the width direction is D, satisfying: 0.01≤D / H≤0.02.

[0016] In some embodiments, the battery cell further comprises:

[0017] A detection port is disposed on the shell component, and the detection port is electrically connected to the sensing element.

[0018] In some embodiments, the shell assembly includes:

[0019] A main housing is provided with the accommodating cavity;

[0020] The cover plate is connected to the main shell and covers the accommodating cavity, and the detection port is exposed on the cover plate.

[0021] In some embodiments, the battery cell further comprises:

[0022] The bridging piece is located in the accommodating cavity, the detection port is electrically connected to the sensing element through the bridging piece, and the bridging piece is configured as an elastic bridging piece.

[0023] In some embodiments, the sensing element is a flexible pressure sensor.

[0024] A battery pack comprises the battery cell described in any one of the above.

[0025] Beneficial effects: The battery cell of the embodiment of the present application includes: a shell assembly having a receiving cavity; a winding core arranged in the receiving cavity, the winding core having a main body and arc portions located on both sides of the main body; a connecting piece arranged in the receiving cavity; a sensing element arranged in the receiving cavity, the sensing element being arranged on the arc portion through the connecting piece to measure the pressure or pressure change of the winding core on the arc portion. The sensing element is arranged on the arc portion of the winding core through the connecting piece. During the battery cycle, the winding core usually deteriorates first at the arc portion. By arranging the sensing element at this position, the pressure or pressure change can be detected earlier than at other positions, and the expansion of the winding core can be sensed in time.

[0026] An embodiment of the present application provides a battery pack, including the above-mentioned battery cell. The battery pack has all the technical features and beneficial effects of the above-mentioned battery cell, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A schematic cross-sectional view of a battery cell according to an embodiment of the present application;

[0029] Figure 2 A top view of a form of the connecting member provided in the embodiment of the present application when the connecting member is an insulating member;

[0030] Figure 3 A top view of another form of the connecting member provided in the embodiment of the present application when the connecting member is an insulating member;

[0031] Figure 4 A schematic diagram of a top view structure when the connecting member provided in an embodiment of the present application is a diaphragm;

[0032] Figure 5 Provided in the embodiments of this application Figure 1 A partial enlarged view of area A in the middle;

[0033] Figure 6 A schematic diagram of the structure of the shell assembly provided in an embodiment of the present application;

[0034] Figure 7 A schematic diagram of the top view of the cover plate provided in an embodiment of the present application;

[0035] Figure numerals: 10 - shell assembly; 11 - accommodating chamber; 12 - main shell; 13 - cover plate; 20 - winding core; 21 - middle part; 22 - arc part; 30 - sensing element; 40 - connecting piece; 50 - detection port; 60 - overlapping piece; 70 - fixing piece; X - width direction. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0037] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "plurality" means two or more, and at least one means one, two or more, unless otherwise clearly and specifically defined.

[0038] As an introduction to the implementation of the present application, a square lithium-ion battery is introduced. As the core of the battery circulates, gas is generated inside the core, causing expansion, and the performance of the battery cell deteriorates rapidly, and there is a lack of early warning means. In order to warn of the degree of expansion of the core, a sensing element is generally installed inside the battery to sense the squeezing force on the sensing element when the core expands, thereby achieving an early warning effect. However, the sensing element is generally installed between the core and the shell, and is connected to the core and the shell at the same time. During the induction process, if the shell is deformed by external force, it will also squeeze the sensing element connected to it, which may cause additional force interference to the sensing element, affecting the sensing element's sensing of the core expansion pressure and reducing the accuracy of the sensing. At the same time, when the sensing element is squeezed by the expansion of the core, it will move to one side, and the structure connected to the sensing element will be pulled, thereby breaking, which will affect the normal detection of the staff.

[0039] In view of this, an embodiment of the present application provides a battery cell to overcome at least one of the above-mentioned technical problems.

[0040] See also Figure 1 , Figure 2 , Figure 3 and Figure 4 In the embodiment of the present application, the battery cell includes a shell assembly 10, a core 20, and a sensing element 30; the shell assembly 10 is the outermost shell of the battery, which can protect the internal structure of the battery. The core 20 is the core component of the battery, which is usually formed by winding a positive electrode, a negative electrode, a diaphragm and an electrolyte. The positive electrode and the negative electrode are the two poles of the battery, responsible for storing and releasing electric charge. The diaphragm plays the role of isolating the positive and negative electrodes to prevent short circuits. The electrolyte is a conductive medium inside the battery that can promote the conduction of electric charge. When manufacturing a square battery core 20, the positive electrode sheet, the negative electrode sheet and the diaphragm are stacked together many times to form a long sheet structure. In order to wind this sheet structure into a compact core 20, it is necessary to wrap it together by winding or stacking. After the winding is completed, the two sides of the core 20 will be arc-shaped. The sensing element 30 can be a pressure-sensitive element, such as a flexible pressure sensor, which plays an important sensing role in the battery cell and can be used to sense the squeezing force of the core 20 on the sensing element 30 during the expansion process.

[0041] The shell assembly 10 is provided with a accommodating cavity 11; the winding core 20 is arranged in the accommodating cavity 11; the sensing element 30 is also arranged in the accommodating cavity 11, and the accommodating cavity 11 provides a good installation environment for the winding core 20 and the sensing element 30. The winding core 20 has a main body 21 and arc portions 22 arranged on both sides of the main body 21, and the arc portions 22 are arc-shaped portions formed by the winding core 20 during the winding process. The battery cell also includes a connector 40, which is also arranged in the accommodating cavity 11. The sensing element 30 is connected to the arc portion 22 through the connector 40, and is used to measure the pressure or pressure change of the winding core 20 on the arc portion 22. After the battery is charged and discharged, due to the deformation of the material (mainly the pole piece and the isolation film), the gap of the inner layer of the core 20 at the corner is too small, and stress concentration is generated along the width direction of the core 20, which causes the core 20 to deform first at the arc portion 22, that is, the core 20 usually deteriorates first at the arc portion 22. Therefore, the sensing element 30 is set on the arc portion 22 of the core 20, which can measure the pressure or pressure change earlier than at other positions, and timely sense the expansion of the core 20, so that early warning information can be issued in time. The connector 40 is connected to the sensing element 30, and the sensing element 30 is fixed on the arc portion 22 through the connector 40. The connector 40 can be a flexible material, and the sensing element 30 and the core 20 are covered together, so that the sensing element 30 fits the arc portion 22. When the arc portion 22 expands, it is restricted by the constraint of the connector 40 and squeezes the sensing element 30, and the sensing element 30 can sense the squeezing force.

[0042] The way in which the connecting member 40 wraps the sensing element 30 and the winding core 20 together can be: the connecting member 40 surrounds or wraps around the outer periphery of the sensing element 30 and the winding core 20; or a part of the connecting member 40 wraps around the outer periphery of the sensing element 30, and the other part of the connecting member 40 is arranged on the winding core 20, and it does not need to completely surround the outer periphery of the winding core 20, but only needs to be connected to the winding core 20. When the winding core 20 expands during recycling, since the sensing element 30 is arranged between the winding core 20 and the connecting member 40, the expanded winding core 20 will push the sensing element 30 to one side, and at the same time, the connecting member 40 will be tightened. A part of the connecting member 40 is connected to the side of the sensing element 30 away from the winding core 20, and abuts against the sensing element 30, so that the expanded arc portion 22 can squeeze the sensing element 30, so that the sensing element 30 can sense the squeezing force of the arc portion 22 on itself during the expansion process.

[0043] The connector 40 can also adhere the sensing element 30 to the arc portion 22 by adhesion. At the same time, the side of the sensing element 30 away from the arc portion 22 is against the shell assembly 10. When the arc portion 22 expands, it can squeeze the sensing element 30. The sensing element 30 can sense the squeezing force to give a timely warning.

[0044] See also Figure 1 , Figure 2 and Figure 3 In some embodiments, the connector 40 may be configured as an insulating member wrapped around the sensing element 30 and the outer periphery of the winding core 20, so as to fix the sensing element 30 on one side of the winding core 20. The insulating member may completely wrap around the sensing element 30 and the outer periphery of the winding core 20, or may wrap around the winding core 20 at both ends and the sensing element 30 in the middle. It should be noted that the insulating member may be an insulating structure that is relatively thin and has a certain strength, such as an insulating tape.

[0045] See also Figure 4 In some embodiments, since the core 20 has a diaphragm for separating the positive electrode and the negative electrode, the connector 40 and the diaphragm of the core 20 are an integrated structure. In other words, the connector 40 can be the diaphragm of the core 20. After the core 20 is wound, the excess diaphragm is extended to cover the body of the core 20 and the sensing element 30, so as to fix the sensing element 30 on the core 20. This method makes the process of covering the core 20 and the sensing element 30 simpler, and it can be completed directly using the structure on the core 20.

[0046] See also Figure 2 and Figure 3 In some embodiments, the battery cell includes a fixing member 70, which is arranged in the accommodating cavity 11. The connector 40 is connected to the core 20 through the fixing member 70. The fixing member 70 can be two parts, which are respectively arranged at both ends of the connector 40, and are both connected to the core 20. The fixing member 70 can also be a whole, and the two ends of the fixing member 70 and the two ends of the connector 40 are respectively connected to form an annular structure, which is wrapped together around the periphery of the sensing element 30 and the core 20 to fix the two. In both cases, the connector 40 is coated on the sensing element 30, so that the sensing element 30 and the shell assembly 10 are separated, and the connector 40 and the shell assembly 10 are also spaced from each other to prevent the shell assembly 10 from affecting the sensing element 30 through the connector 40. This ensures that when the shell assembly 10 is deformed, it will not cause additional force interference to the sensing element 30. When the winding core 20 expands, the position of the sensing element 30 will also expand, and the connecting member 40 will be tightened. The connecting member 40 will abut against the sensing element 30, so that the winding core 20 squeezes the sensing element 30, so that the sensing element 30 can sense the squeezing force of the winding core 20 on itself during the expansion process.

[0047] See also Figure 5In some embodiments, along the width direction X of the shell assembly 10, the maximum dimension of the shell assembly 10 is H, and the value of H can be directly measured by a dimension measuring tool (such as a triangle ruler, a vernier caliper, etc.). The connector 40 fixes the sensing element 30 to one side of the winding core 20 in the width direction X, and the minimum distance between the connector 40 and the shell assembly 10 in the width direction X is D. The value of D can be measured by disassembling the battery and using a dimension measuring tool (such as a vernier caliper, an imager, etc.); satisfying: 0.01≤D / H≤0.02. Among them, the value of D / H can be any value among 0.01, 0.012, 0.014, 0.016, 0.018, 0.02, or a range value between any two values. D / H is in the range of 0.01 to 0.02, which can meet the normal expansion requirements of the winding core 20; it also ensures that there is a certain distance between the connector 40 and the shell assembly 10 in the width direction X. When the shell assembly 10 is deformed by external force, under reasonable deformation conditions, the inner wall of the shell assembly 10 will not squeeze the connector 40, thereby avoiding force interference to the sensing element 30 when the shell assembly 10 is deformed.

[0048] See also Figure 1 In some embodiments, the battery cell further includes a detection port 50, which is disposed on the shell assembly 10, and the detection port 50 is electrically connected to the sensing element 30. Since the detection port 50 is electrically connected to the sensing element 30, after the sensing element 30 senses the expansion and extrusion pressure of the winding core 20, the staff can directly receive the electrical signal emitted by the sensing element 30 through the detection port 50, so as to facilitate the understanding of the extrusion pressure of the winding core 20 on the sensing element 30. As the extrusion pressure on the sensing element 30 changes, the electrical signal transmitted by the sensing element 30 will also change. The change in the extrusion pressure on the sensing element 30 can be indicated by measuring the change in characteristic parameters such as voltage and resistance on the detection port 50. At the same time, the detection port 50 is also disposed on the shell assembly 10, so that a specific detection area is directly formed on the shell assembly 10, and the staff can detect the extrusion pressure of the winding core 20 inside the battery on the sensing element 30 only on the outside of the battery. Among them, the staff can detect the detection port 50 through the corresponding detection tool, and can directly use the probe, wiring harness, etc. to collect signals and parameters in the form of point contact or welding during the detection. During the signal and parameter acquisition process, a comparison object may be selected for comparison detection. The comparison object may be a positive pole, a negative pole, a shell assembly 10, or a comparison object independent of the battery. Within a certain period of time, multiple sets of parameters of the detection port 50 are collected for comparison, or the parameters of the detection port 50 and the comparison object are collected for comparison at the same time, so as to identify the pressure change inside the winding core 20; the real-time battery life is characterized by the relationship between the pressure change and the battery life.

[0049] See also Figure 6 and Figure 7 In some embodiments, the shell assembly 10 includes a main shell 12 and a cover plate 13. The main shell 12 is provided with a accommodating cavity 11 for accommodating specific components. The cover plate 13 is connected to the main shell 12 and covers the accommodating cavity 11, providing a good installation environment for the structure arranged inside the accommodating cavity 11, and can effectively protect the internal structure from interference and damage from the external environment. At the same time, the detection port 50 is exposed on the cover plate 13. The detection port 50 can be a plug interface for plugging in an external detection device, so that the detection device can detect the electrical signal transmitted from the sensing element 30 to the detection port 50. By being exposed on the cover plate 13, the detection port 50 can be conveniently connected to the outside world and perform the required operations.

[0050] See also Figure 1 In some embodiments, the battery cell further includes a lap joint 60, which is located in the accommodating cavity 11. The detection port 50 is electrically connected to the sensing element 30 through the lap joint 60, and the lap joint 60 is configured as an elastic lap joint 60. The lap joint 60 may be a metal spring or a metal spring, which is used to electrically connect the detection port 50 to the sensing element 30. When the winding core 20 expands, the winding core 20 will cause the sensing element 30 to shift in position to a certain extent, which will cause the sensing element 30 to pull the lap joint 60. By configuring the lap joint 60 as an elastic structure, a certain degree of deformation may occur when the sensing element 30 pulls the lap joint 60, without causing damage to the lap joint 60, thereby ensuring that the electrical signal transmitted by the sensing element 30 can be detected through the detection port 50.

[0051] A battery pack for storing and releasing electric energy, comprising a housing and a plurality of battery cells as described above, wherein the plurality of battery cells are housed in the housing. The battery pack may be a battery module, a battery pack, a battery cluster, a battery stack, a battery tower, a battery array, or other charging and discharging structure composed of a plurality of battery cells. Battery cells include but are not limited to lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of the present disclosure are not limited thereto.

[0052] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0053] The battery cells and battery packs provided in the embodiments of the present application are introduced in detail above, and the principles and implementation methods of the present application are explained by using specific examples. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell, characterized in that: include: A shell assembly (10) having a receiving cavity (11); A winding core (20) is arranged in the accommodating cavity (11), wherein the winding core (20) comprises a main body (21) and arc portions (22) located on both sides of the main body (21); A connecting member (40) is arranged in the accommodating cavity (11); A sensing element (30) is disposed in the accommodating cavity (11); the sensing element (30) is disposed on the arc portion (22) via the connecting member (40) to measure the pressure or pressure change of the winding core (20) on the arc portion (22).

2. The battery cell according to claim 1, characterized in that: The connecting member (40) is configured as an insulating member that covers the outer periphery of the sensing element (30) and the winding core (20).

3. The battery cell according to claim 1, characterized in that: The connecting member (40) and the diaphragm of the winding core (20) are an integrated structure, and the connecting member (40) covers the sensing element (30) to fix the sensing element (30) on the winding core (20).

4. The battery cell according to claim 1, characterized in that: The battery cell comprises: A fixing member (70) is disposed in the accommodating cavity (11), and the connecting member (40) is connected to the winding core (20) via the fixing member (70); The connecting member (40) is coated on the sensing element (30), and the connecting member (40) is arranged between the sensing element (30) and the shell component (10) to separate the sensing element (30) and the shell component (10), and the connecting member (40) and the shell component (10) are separated from each other.

5. The battery cell according to claim 4, characterized in that: Along the width direction (X) of the shell component (10), the maximum dimension of the shell component (10) is H; The connecting member (40) fixes the sensing element (30) to one side of the arc portion (22) in the width direction (X), and the minimum distance between the connecting member (40) and the shell component (10) in the width direction (X) is D; Satisfies: 0.01≤D / H≤0.

02.

6. The battery cell according to claim 1, characterized in that: The battery cell further comprises: A detection port (50) is arranged on the shell component (10), and the detection port (50) is electrically connected to the sensing element (30).

7. The battery cell according to claim 6, characterized in that: The shell assembly (10) comprises: A main housing (12) is provided with the accommodating chamber (11); A cover plate (13) is connected to the main housing (12) and covers the accommodating cavity (11); the detection port (50) is exposed on the cover plate (13).

8. The battery cell according to claim 6, characterized in that: The battery cell further comprises: The bridging piece (60) is located in the accommodating cavity (11); the detection port (50) is electrically connected to the sensing element (30) via the bridging piece (60); and the bridging piece (60) is configured as an elastic bridging piece (60).

9. The battery cell according to claim 1, characterized in that: The sensing element (30) is a flexible pressure sensor.

10. A battery pack, characterized in that: The invention comprises the battery cell according to any one of claims 1 to 9.

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